I am making key lime tartlets for a Gala/fundraiser in a week and wanted to practice. It’s a good thing I did. The meringue never whipped to peaks. I binned the first attempt and made some minor changes to the second, which resulted in perfect, smooth, silky Italian meringue.

I used a kitchen blowtorch to brown the tops. The lime zest incorporated in the filling and lightly dusted on the top added the tartness to balance the meringue.
Key Lime Tartlets
Gluten Free suggestions at the end
INGREDIENTS
SHELL
• 100 g cold butter cut into small cubes
• 200 g all-purpose flour
• 60 g icing sugar
• ½ tsp vanilla
• ¼ tsp salt
• 2 eggs – 1 for the dough and the other 1 reserved for an egg wash (try egg white only for Almond flour.)
FILLING
• zest (grated rind) of 1 lime
• 4 large egg yolks
• 14-ounce can (397g) sweetened condensed milk, (1 1/4 cups)
• 3/4 cup (170g) Key lime juice or lime juice
• 1/8 to 1/4 teaspoon lime oil, optional
METHOD
SHELL
- Mix butter with sugar until well incorporated 3-5 min
- Add salt then vanilla
- Add egg and mix 3-5 min – for almond flour: suggest using only the egg white to reduce the moisture in the dough
- Stir in flour. Mix by hand until incorporated and forms a thick smooth(ish) sticky dough
- Cover with plastic and refrigerate for 30 min
- Pre-heat oven to 350 degrees
- Butter tartlet pans, or use non-stick pans
For AP Flour
a. Roll dough on floured surface
b. Cut into circles 1” larger diameter than the mold
c. Press into molds filling all parts of the mold
For Almond Flour
a. Roll dough between parchment paper to about ⅛” thick
b. Freeze rolled dough still between parchment paper until firm: 20 – 30 minutes
c. Cut frozen dough to rounds about 1” larger diameter than the mold. Cut all the rounds at once while still frozen. I used an offset spatula to remove the circles from the parchment paper. Keep the spatula clean.
d. Lay tart dough circles over molds. This allows the dough to thaw slightly and be pressed into the molds and fill all crevices. - Pinch off excess with wet fingers. (Dough is sticky)
- Prick holes in bottom and sides of formed dough
- Fill tarts with pastry weights (I put beans in mini cupcake papers
- Paint edges of the tartlet with the egg wash.
- Bake in preheated oven 350 deg F (175 C) for 6-8 min
- Remove pastry weights and bake an additional 4-6 minutes to dry the bottoms. Bake until the edges are begin to turn light brown
- Immediately remove from pans and cool on a wire rack
FILLING
- Whisk the lime zest and egg yolks at high speed of an electric mixer for about 4 minutes. The mixture will lighten in color and thicken somewhat, appearing similar to Hollandaise sauce.
- Stir in the sweetened condensed milk, mixing until smooth. Beat at high speed for 3 minutes; the filling will become slightly thicker and gain a bit of volume.
- Add the lime juice, stirring just to combine. The mixture will thicken again. Add lime oil to taste.
- PIPE the filling into the crust and return the tart (on the baking sheet) to the oven. Bake the tart for 12 to 18 minutes, until it appears set around the edges though still a bit wobbly in the center. The center should read about 145°F on a digital thermometer.
- Remove the tart from the oven and cool to room temperature. Refrigerate for several hours before serving.
- Once chilled, serve the key lime pies cold with whipped cream, or merengue and a lime slice or zest, if desired.
- Store leftover pies in the refrigerator (covered) for up to 1 week. If they last that long!
Notes
Make Ahead & Freezing Instructions: Up to 1 day in advance, you can prepare the crust ingredients and the filling ingredients separately. Store each covered tightly in the refrigerator until ready to assemble and bake. You can bake the key lime pies and store in the refrigerator for 1 day before serving. Key lime pies freeze well, up to 2–3 months. Thaw overnight in the refrigerator before serving.
Gluten Free:
Substitute Almond flour for AP flour or 1:1 Almond and coconut flours
Add 1 Tbl psyllium husk per cup of almond flour.
ITALIAN MERINGUE
INGREDIENTS
• 80g (or 0.4 cup or 6.5 Tbl) granulated sugar
• 30ml (or 1/8 cup) water
• 60g (or ¼ cup) egg whites (about 2 large egg whites)
• 20 g icing sugar
METHOD
- Whisk the egg whites into a light and fluffy foam, using an electric (stand) mixer.
- Add the icing sugar and continue whipping until you’ve got a glossy stable foam. It should stay in place if you turn the bowl upside down. Set aside.
- Add the granulated sugar and water to a pan and bring to a boil. Once all the sugar has dissolved, refrain from stirring. Continue boiling at moderate/high heat while continuously keeping an eye on the temperature.
- Once the solution has reached 121°C (250°F), take it from the heat immediately*.
- While SLOWLY beating the egg whites, gently pour the hot sugar solution into the whipped egg whites (this is where the stand mixer comes in handy!).
- Once all the sugar syrup is in, turn up the speed to high and continue whisking until the foam is lukewarm.
- Use the meringue immediately to top whatever it is you want to cover.
NOTES
Italian meringue can be made two days in advance and stored in the fridge until needed (covered with plastic wrap). Store in a piping bag, sealing the tip,