Italian Key Lime Pie with Ricotta and Lemon

Italian key lime pie is a creamy citrus tart inspired by American Key lime pie, with ricotta adding a gentle Italian touch. A crisp graham cracker crust holds a tangy filling of condensed milk, lime, lemon, and egg yolks; chilling it thoroughly makes each slice neat and silky.

Ingredients

1½ cups (150 g) finely crushed graham cracker crumbs
5 tablespoons (70 g) unsalted butter, melted
2 tablespoons (25 g) granulated sugar
¼ teaspoon fine salt
1 can (14 ounces / 396 g) sweetened condensed milk
½ cup (120 g) whole-milk ricotta, drained if watery
4 large egg yolks (about 72 g)
½ cup (120 ml) Key lime juice, freshly squeezed or bottled
1 tablespoon (15 ml) lemon juice
1 teaspoon finely grated Key lime zest, plus extra to serve
½ cup (120 ml) cold heavy cream, for serving (optional)
1 teaspoon powdered sugar, for serving (optional)

Instructions

Heat the oven to 350°F (175°C). Set a 9-inch (23 cm) pie plate on a baking sheet. If using fresh Key limes, zest them before juicing; you will need about ½ cup juice, usually from 1 to 1½ pounds (450–680 g) of small limes. Bottled Key lime juice is a practical substitute and gives a consistent tart flavor. Regular Persian lime juice works too, though it tastes less floral and can be slightly less sharp.
In a medium bowl, mix the graham cracker crumbs, melted butter, sugar, and salt until evenly moistened. Press firmly across the bottom and up the sides of the pie plate, using the flat bottom of a measuring cup to compact it. Bake for 8 minutes, then set the crust aside while you make the filling. Leave the oven on.
Whisk the condensed milk and ricotta in a large bowl until mostly smooth. Whisk in the egg yolks, lime juice, lemon juice, and lime zest just until combined. A few tiny ricotta flecks are fine; avoid prolonged whisking, which can make the filling foamy. Pour it into the warm crust and smooth the top.
Bake for 15–17 minutes, until the edges look set and the center still has a slight, gentle wobble. For food safety, egg dishes should reach the USDA FSIS safe minimum internal temperature of 160°F (71°C); check the center with a food thermometer without touching the crust. If it has not reached that temperature, continue baking briefly and check again. The center firms further as the pie cools.
Transfer the pie plate to a rack and cool for 1 hour at room temperature. Cover loosely and refrigerate for at least 4 hours, or until fully cold and sliceable. For a clean cut, use a sharp knife wiped between slices.
If desired, whip the cold heavy cream with the powdered sugar to soft peaks just before serving. Spoon or pipe it over the pie and finish with a little extra lime zest.

Tips

Drain watery ricotta: If liquid collects in the container, drain the ricotta in a fine sieve for 15–30 minutes. This keeps excess moisture from loosening the filling.
Measure juice accurately: Use ½ cup (120 ml), not the juice of a fixed number of limes; fruit size and juiciness vary. Strain fresh juice to remove seeds and pulp.
Watch the center: The pie should not be browned or fully rigid in the oven. Overbaking can make the filling grainy or cause cracks; use the thermometer for safety and take the pie out once it meets the temperature requirement.
Press the crust firmly: Compact crumbs evenly up the sides so the crust holds together when cut. If the crust crumbles, it may need more even pressing or slightly finer crumbs.

Serving Suggestions

Serve the pie cold, in modest slices, with softly whipped cream and a fine grating of lime zest. Fresh berries, such as raspberries or strawberries, add a sweet-tart contrast without competing with the citrus. For a simple finish, offer the pie plain; its creamy filling and buttery crust are flavorful on their own.

Variations

For a more pronounced Italian character, replace the graham crackers with finely crushed plain digestive biscuits or crisp Italian-style biscuits; the crust will be less honeyed and may need an extra teaspoon or two of melted butter if it seems dry. If Key limes are unavailable, Persian limes are an easy substitute, while the tablespoon of lemon juice keeps the citrus flavor rounded.

For a slightly lighter, less distinctly ricotta-forward filling, use ¼ cup (60 g) ricotta and increase the condensed milk by ¼ cup (about 80 g); the result will be sweeter and denser. You can also omit the optional whipped cream or serve it separately. Avoid replacing the condensed milk with ordinary milk: condensed milk supplies both concentrated dairy solids and the sweetness needed for the filling to set properly.

Storage and Reheating

Refrigerate the pie within 2 hours of baking, once it has cooled enough to handle; do not leave it at room temperature for longer than 2 hours. Keep it covered in the refrigerator and eat within 3–4 days. Whipped cream is best added just before serving. For longer storage, freeze the unadorned pie, tightly wrapped, for up to 1 month; thaw overnight in the refrigerator. This chilled dessert is served cold and should not be reheated.

Frequently Asked Questions

Can I use regular limes instead of Key limes?
Yes. Use the same measured amount of Persian lime juice. The flavor will be a little less delicate and more familiar, but lemon juice and zest still keep the filling bright.

Do I have to use ricotta?
No. For a more classic Key lime pie texture, omit the ricotta and use 1 can (14 ounces / 396 g) condensed milk with the same egg yolks and citrus. The result will be denser and more intensely sweet-tart, without the Italian-inspired dairy note.

Why is my filling runny?
It may not have baked long enough, may have been cut before chilling, or the ricotta may have contained excess liquid. Confirm the center reaches 160°F (71°C), then chill the pie for at least 4 hours before slicing.

Can I make the pie ahead?
Yes. Bake and chill it up to 2 days before serving, keeping it covered in the refrigerator. Add whipped cream and fresh zest shortly before bringing it to the table.

Can I make it without a graham cracker crust?
Yes. Use an equal weight of finely crushed digestive biscuits or plain crisp cookies, then mix with the same butter, sugar, and salt. Check the texture before pressing: crumbs should hold together when squeezed, but should not feel greasy.

How can I tell when the pie is set?
The edges should look firm while the center retains a slight wobble, and the filling must reach the safe temperature specified in the baking step. It will become firmer as it cools and chills, so do not wait for the center to look completely solid in the oven.

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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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