Zucchini Strata Recipe with Cheddar and Fresh Herbs

Zucchini strata is a savory baked casserole of bread, eggs, cheese, and tender zucchini, with a custardy center and browned top. This version uses sharp cheddar and fresh herbs; it makes a satisfying brunch or an easy meatless dinner, and letting the bread soak before baking helps the strata hold together.

Ingredients

1 tablespoon (15 ml) olive oil, plus a little for the baking dish
1 medium yellow onion, about 1 cup (150 g) finely chopped
2 medium zucchini, about 1 lb (450 g), cut into ¼-inch (6 mm) slices
1 teaspoon (5 g) fine salt, divided
½ teaspoon (1 g) freshly ground black pepper
8 cups (280 g) day-old crusty bread, cut into 1-inch (2.5 cm) cubes
2 cups (225 g) sharp cheddar cheese, grated
8 large eggs
2 cups (480 ml) whole milk
1 tablespoon (15 ml) Dijon mustard
1 teaspoon (2 g) fresh thyme leaves, or ½ teaspoon (1 g) dried thyme
¼ cup (10 g) chopped fresh parsley, plus extra to serve
¼ cup (25 g) finely grated Parmesan

Instructions

Heat the oven to 350°F (175°C). Lightly oil a 9-by-13-inch (23-by-33 cm) baking dish. If your bread is fresh and soft, spread the cubes on a baking sheet and toast for 10–12 minutes, until dry on the surface but not browned. Set aside.
Warm the olive oil in a large skillet over medium heat. Add the onion and cook for 4–5 minutes, stirring, until softened. Add the zucchini, half the salt, and the pepper. Cook for 6–8 minutes, stirring occasionally, until the zucchini is just tender and some of its released liquid has evaporated. Avoid cooking it to mush. Take the pan off the heat and let the vegetables cool for about 10 minutes.
In a large bowl, whisk the eggs, milk, Dijon, thyme, parsley, and remaining salt until evenly combined. Stir in the cheddar. Add the bread cubes and cooled vegetables, then fold gently so the bread is coated without being crushed.
Transfer the mixture to the prepared dish and spread it evenly. Sprinkle the Parmesan over the top. Leave it to soak for 20 minutes at room temperature; this gives the bread time to absorb the egg mixture. For a make-ahead option, cover and refrigerate it instead, following the storage and timing guidance below.
Bake uncovered for 45–55 minutes, until the top is golden and the center is set. Check the center with a food thermometer: egg dishes should reach the USDA FSIS safe minimum internal temperature of 160°F (71°C). If the top browns before the center is ready, loosely cover the dish with foil for the remaining baking time.
Rest the strata for 10 minutes before cutting. Sprinkle with extra parsley and serve warm. The short rest makes portions easier to lift from the dish.

Tips

Choose a sturdy, low-moisture bread such as sourdough or country loaf. Very soft sandwich bread can turn pasty; if that is what you have, toast it until dry before mixing.
Cook the zucchini first to drive off excess water. Skipping this step can leave a watery casserole, especially if the zucchini is large or particularly juicy.
Grate cheese from a block if possible. It melts smoothly and lets you adjust the sharpness; pre-shredded cheese also works but may give a slightly less even melt.
For a planned overnight bake, assemble the strata, cover, and refrigerate promptly. Add about 10–15 minutes to the baking time if it goes into the oven cold, and use the thermometer—not appearance alone—to confirm the center is done.

Serving Suggestions

Serve warm wedges with a crisp green salad dressed with lemon or a light vinaigrette. Fresh fruit, sliced tomatoes, or a bowl of berries also make a good brunch side. For a more substantial meal, pair the strata with roasted potatoes or a simple vegetable soup. Its savory cheese and herbs work well with both breakfast and lunch dishes, so there is no need to reserve it for a particular time of day.

Variations

Replace up to half the cheddar with Gruyère, fontina, or Monterey Jack for a different melting cheese. Gruyère brings a nutty flavor, while Monterey Jack is milder. You can swap the thyme and parsley for 1 tablespoon (3 g) chopped basil or chives; stir delicate herbs into the egg mixture rather than cooking them with the zucchini.

To add other vegetables, use about 1 cup (100 g) sliced mushrooms or chopped red bell pepper. Cook them with the onion until their moisture has mostly evaporated before combining them with the zucchini. For a little heat, add ¼ teaspoon (0.5 g) red pepper flakes. Avoid adding extra wet ingredients, such as fresh tomato, without first draining or cooking them down.

Storage and Reheating

Refrigerate leftovers within 2 hours of baking, in a covered container or tightly covered in the dish. Keep them refrigerated at 40°F (4°C) or below and use within 3–4 days. Reheat individual portions in a microwave or covered baking dish until the center reaches 165°F (74°C), the USDA FSIS temperature for reheated leftovers. To reheat a larger portion, cover and warm in a 325°F (165°C) oven; uncover briefly at the end if you want to restore some crispness.

For advance assembly, cover the unbaked strata and refrigerate it for up to 24 hours. Bake it within that window, allowing extra time if chilled. You can also freeze baked portions in airtight packaging for up to 2 months for best quality; thaw overnight in the refrigerator, then reheat to 165°F (74°C). Do not leave the casserole at room temperature for more than 2 hours, or 1 hour when the room is above 90°F (32°C).

Frequently Asked Questions

Can I make zucchini strata the night before?
Yes. Assemble it, cover the dish, and refrigerate promptly for up to 24 hours. Bake it straight from the refrigerator, allowing roughly 10–15 extra minutes as needed, and check that the center reaches 160°F (71°C).

Do I have to peel the zucchini?
No. The skin is tender when cooked and helps the slices keep their shape. Wash and dry the zucchini, trim the ends, and leave the peel on.

Why is my strata watery?
Zucchini contains a lot of moisture. Cooking it before assembly helps evaporate excess liquid; also avoid using fresh bread without drying it or adding vegetables with unremoved liquid. Let the strata rest before serving so the custard can settle.

How do I know when the center is cooked?
The top should be browned and the middle should no longer look liquid, but a thermometer provides the reliable check: insert it into the center, away from the dish, and confirm 160°F (71°C) for this egg dish.

Can I use frozen zucchini?
Yes, but thaw it completely and squeeze out as much liquid as possible. Cook it briefly in the skillet to evaporate remaining moisture. Its texture will be softer than fresh zucchini, but it will still work in the casserole.

Can I assemble the casserole without soaking it for 20 minutes?
The soak helps the bread absorb the custard and gives a more even texture. If you are short on time, let it stand for at least 10 minutes, then bake; the center may be a little less uniform, so check doneness carefully.

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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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