Marrow jam is a sweet, soft-set preserve made by simmering summer squash with sugar, tart apple, lemon and ginger. The apple and lemon help balance the marrow’s mild flavor and encourage a gentle set; spoon it onto toast, scones or a cheese board rather than treating it like a savory squash relish.
Ingredients
- 2 lb 8 oz prepared marrow (1.13 kg), peeled, seeded and cut into small dice; weigh it after trimming
- 5 cups granulated sugar (1 kg)
- 2 medium tart apples (about 10½ oz / 300 g total), cored and coarsely grated; leave the skin on for its natural pectin
- 2 medium lemons, finely zested and juiced (about ½ cup / 120 ml juice)
- 1 tablespoon finely grated fresh ginger (6 g)
- ⅛ teaspoon fine salt (about 0.7 g)
Instructions
- Prepare the marrow. Wash and dry the marrow, then peel it with a vegetable peeler. Cut it lengthwise and scoop out the seeds and any spongy center with a spoon. Dice the firm flesh into pieces about ½ inch (1.25 cm) across so they soften evenly. Weigh 2 lb 8 oz (1.13 kg) after trimming; if your marrow is larger, save the extra for another dish.
- Combine and macerate. Put the diced marrow in a large, heavy-bottomed nonreactive pot. Add the sugar, grated apples, lemon zest and juice, ginger, and salt. Stir thoroughly, cover, and leave at room temperature for 1 hour. This rest draws liquid from the marrow and begins dissolving the sugar, so you should have a syrupy mixture before it goes on the stove. If the sugar still looks dry in places, stir again before heating.
- Warm gently until the sugar dissolves. Set the uncovered pot over medium-low heat. Stir frequently, scraping the base and corners with a heatproof spatula, until the liquid is clear and no crystals remain, about 8–12 minutes. Avoid turning the heat up to hurry this stage: undissolved sugar can catch on the bottom during the later boil and give the jam a scorched flavor.
- Simmer and reduce. Bring the mixture to a steady boil, then lower the heat enough to maintain an active, even simmer. Cook uncovered for about 50–60 minutes, stirring every few minutes at first and more often as it thickens. The marrow should become translucent and tender, and the liquid should look glossy rather than watery. Keep the pot at a moderate simmer; a violent boil can splatter hot syrup and make the bottom more likely to scorch.
- Check the set. After about 55 minutes of simmering, put a teaspoon of jam on a chilled plate and return it to the freezer for 2 minutes. Push the edge with a fingertip: if the surface wrinkles slightly and the trail does not quickly fill with liquid, the jam is ready. If it runs freely, simmer for another 5–8 minutes and test again. Repeat as needed, stirring carefully. A soft set is normal for marrow jam, and it will thicken further as it cools. The exact cooking time depends on the water content of the marrow and the width of the pot.
- Fill clean containers. Take the pot off the heat and let the bubbling settle for a minute. Spoon the hot jam into clean, heat-safe jars or lidded containers, leaving a little headspace so it is easy to stir later. Wipe any drips from the rims, let the containers cool uncovered until no longer hot, then cover and refrigerate. Do not treat these as shelf-stable preserves or store them at room temperature.
- Cool before serving. Allow about 45 minutes for the filled containers to cool to room temperature, then chill them. The flavor becomes rounder and the texture more cohesive after several hours in the refrigerator, though the jam can be tasted once cool.
Tips
- Choose a firm marrow. Very mature marrow can have watery, fibrous flesh and large seeds. If yours is particularly seedy, remove the soft center generously and weigh the trimmed flesh; a firmer squash gives a cleaner texture and usually needs less reduction.
- Use a wide pot and stir the base. A broad, heavy saucepan lets moisture evaporate without requiring an excessively long boil. Once the mixture thickens, sugar-rich jam can catch quickly, so run the spatula across the base and into the corners every few minutes.
- Let the plate test guide you. The clock is an estimate, not a guarantee. If the sample is still runny, give the pot a few more minutes; if it firms up too much on the cold plate, take the pot off the heat. Do not keep boiling simply to make every piece of marrow disappear—the small translucent dice are part of the jam’s texture.
- Keep the batch refrigerated. This recipe is for a small refrigerator-stored batch, not a validated canning formula. Use clean containers, refrigerate promptly after cooling, and freeze what you will not use within the recommended refrigerator window.
Serving Suggestions
Spread marrow jam thinly on buttered toast, warm scones or an English muffin. Its lemon and ginger notes work especially well with plain breads and lightly salted butter, which leave room for the fruit-like sweetness. For breakfast, add a spoonful to porridge or plain yogurt, or swirl a little through rice pudding just before serving.
It also makes a useful sweet counterpoint on a savory plate. Serve a small dish alongside mature cheddar, farmhouse-style cheese or a sharp goat cheese, with crackers or crusty bread. A teaspoon can brighten a ham or roast pork sandwich, but use it as a condiment rather than a thick spread so its sweetness does not overwhelm the other fillings. For dessert, spoon it over vanilla ice cream or use it between layers of a simple sponge cake.
Variations
More pronounced ginger: Increase the fresh ginger to 1½ tablespoons (9 g), or add 1 tablespoon (15 g) finely chopped crystallized ginger during the last 10 minutes of cooking. Crystallized ginger adds chewy pieces and extra sweetness, so the finished jam will taste less sharply gingery than a version made with fresh root.
Warm spice: Add one small cinnamon stick while the jam simmers and remove it before filling the containers. A pinch of ground cardamom can also complement the lemon, but use a light hand; too much spice can hide the mild marrow flavor.
Orange and lemon: Replace the zest of one lemon with the finely grated zest of one orange, while keeping the lemon juice in the recipe. Orange makes the aroma sweeter and softer, while the lemon juice preserves the tart balance.
Chunkier or smoother texture: For a more distinct dice, cut the marrow into ¾-inch (2 cm) cubes and expect a slightly longer simmer. For a smoother spread, mash a portion of the cooked marrow against the side of the pot with a spoon before the final set test. Avoid blending the hot mixture in a sealed blender, where steam can build pressure.
Storage and Reheating
Keep the jam in clean, covered containers in the refrigerator and use it within 2–3 weeks for the best quality. Refrigerate it within 2 hours of cooking; do not leave the containers out overnight. Always use a clean spoon to serve, and discard the batch if you notice mold, an unusual smell or unexpected bubbling.
For longer storage, freeze the jam in freezer-safe containers, leaving about ½ inch (1.25 cm) of space at the top for expansion. Use within 3 months for best quality, then thaw it overnight in the refrigerator and stir before serving. Jam is normally eaten cold, so reheating is not necessary. If you want it warm for a sauce or topping, heat only the portion needed in a small saucepan over low heat, stirring until loosened; do not repeatedly warm and cool the whole batch.
Frequently Asked Questions
What is marrow in this recipe?
Marrow is a large, mature summer squash, commonly sold in the United Kingdom and similar in flavor to zucchini or courgette. Choose one with firm flesh. If marrow is unavailable, use large zucchini, trim away the seedy center if it is soft, and weigh the prepared flesh to match the recipe.
Can I use zucchini instead of marrow?
Yes. Use 2 lb 8 oz (1.13 kg) of prepared zucchini. Smaller zucchini may have fewer large seeds and a firmer center, so they can be easier to trim. The flavor will remain mild, and the jam may reach its set point a little sooner if the zucchini contains less water; use the plate test rather than relying only on the stated time.
Why is my marrow jam still runny?
Marrow contains plenty of water and little natural pectin, so a wet squash or a narrow pot can make the reduction take longer. Return the mixture to a simmer and cook it in 5–8 minute increments, testing a small sample on a chilled plate each time. It also thickens as it cools, so judge the final texture only after the sample has chilled for the full 2 minutes.
Can I reduce the sugar?
Reducing the sugar changes both the sweetness and the way the mixture sets, so this recipe’s timing and texture may no longer apply. For a lower-sugar version, use a tested recipe designed for low-sugar pectin and follow the pectin maker’s quantities and method; simply cutting the sugar here can leave you with a thinner, more perishable jam.
Can I make the jam without ginger?
Yes. Leave out the ginger for a gentler lemon-and-apple flavor, or replace it with the cinnamon variation. The ginger is for flavor rather than setting, so omitting it does not change the cooking method. Keep the apples and lemon juice as written, since they help balance the marrow and support the set.
Can I keep the filled jars in a cupboard?
No. This recipe has not been formulated or processed as a shelf-stable canned preserve. Store it in the refrigerator or freezer, even if a lid seems to have sealed as the containers cool. For cupboard storage, choose a tested canning recipe and follow its specific ingredients and processing directions rather than adapting this one.
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- Marrow and Ginger Jam: A Bright, Spiced Preserve
- Marrow and Ginger Chutney Recipe, Step by Step
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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