1-Step 1: Making the Tart Dough First, cream the cold butter and sugar in a food processor until the mixture is light and fluffy. Add one whole egg and the yolk of the second egg, then pulse to combine everything smoothly. Next, add the flour and salt; pulse until the dough forms a ball. If the dough feels too dry, add the reserved egg white. Shape the dough into a disk and chill it for 10 to 20 minutes to keep it easy to work with.

2-Step 2: Rolling and Chilling the Dough Roll the chilled dough on a lightly floured surface to about 1/4 inch thick. Transfer it to a tart pan, pressing it evenly without stretching, and chill it again until the filling is ready. Remember, there’s no need to grease the pan since the dough has enough fat to prevent sticking.

3-Step 3: Preparing the Berry Filling Preheat your oven to 350°F (175°C). In a bowl, toss the blueberries and sliced strawberries with the sugar, lime zest and juice, and flour. This mixture creates a fresh, jammy filling that pairs perfectly with the buttery crust.

4-Step 4: Assembling and Baking Place the berry mixture into the tart shell and dot it with the small pieces of butter to enrich the flavors. Bake for 1 hour to 1 hour 20 minutes, until the crust edges turn light golden brown. After baking, cool the tart for about 1 hour so the filling sets properly.

5-Step 5: Finishing Touches Warm the fruit jam and brush it over the tart before serving for a shiny glaze. You can serve it with ice cream or whipped cream for an extra treat. For dietary adjustments, use vegan sweeteners or ensure ingredients are gluten-free certified.