Follow these step-by-step instructions to create perfect Lemon Curd Tartlets. We’ll start with making the sweet shortcrust pastry, then move on to the tangy lemon curd, and finally assemble and bake these delightful treats.

Part 1: Making the Sweet Shortcrust Pastry

1. Combine Dry Ingredients: In a large bowl, whisk together the all-purpose flour and salt. This ensures the salt is evenly distributed throughout the dough.
2. Incorporate Cold Butter: Add the cubed cold butter to the flour mixture. Using your fingertips or a pastry blender, cut the butter into the flour until the mixture resembles coarse crumbs. You should still see small pieces of butter, which is essential for flakiness.
3. Add Sugar and Egg Yolk: Stir in the granulated sugar until combined. Then, add the egg yolk to the mixture.
4. Add Ice Water Gradually: Begin adding ice water, one tablespoon at a time, mixing gently after each addition. Mix until the dough just comes together into a shaggy mass. Be careful not to overmix, as this can develop the gluten and make the pastry tough.
5. Form Dough into a Disc: Turn the dough out onto a lightly floured surface. Gently bring the dough together into a disc about 1 inch thick. Wrap the disc tightly in plastic wrap.
6. Chill the Dough: Refrigerate the dough for at least 1 hour, or preferably 2 hours. This chilling time allows the gluten to relax and the butter to firm up, making the dough easier to roll and preventing shrinkage during baking.
7. Preheat Oven and Prepare Tartlet Pans: Preheat your oven to 375°F (190°C). Lightly grease your tartlet pans (typically 4-inch diameter) or a muffin tin if you are making smaller tartlets.
8. Roll Out and Shape the Pastry: On a lightly floured surface, roll out the chilled pastry disc to about 1/8-inch thickness. Use a cookie cutter or a knife to cut out circles slightly larger than your tartlet pans.
9. Line Tartlet Pans: Gently press the pastry circles into the tartlet pans, ensuring they fit snugly into the corners and up the sides. Trim off any excess pastry hanging over the edges.
10. Dock the Pastry: Prick the bottom of each pastry shell several times with a fork. This process, called docking, prevents the pastry from puffing up during baking.
11. Blind Bake the Crusts (Optional but Recommended): For extra crisp crusts, you can blind bake them. Line each pastry shell with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes. Remove the parchment paper and weights and bake for another 5-7 minutes, or until the crusts are lightly golden brown. If you prefer a softer crust, you can skip blind baking and fill the unbaked crusts with lemon curd directly. Reduce oven temperature to 350°F (175°C) for baking with the curd.

Part 2: Making the Tangy Lemon Curd Filling

1. Combine Ingredients in a Heatproof Bowl: In a medium-sized heatproof bowl (stainless steel or glass), whisk together the granulated sugar, lemon zest, lemon juice, eggs, and egg yolks. Ensure everything is well combined.
2. Cook Over a Double Boiler (or Bain-Marie): Place the bowl over a saucepan of simmering water, ensuring the bottom of the bowl does not touch the water. This creates a gentle, indirect heat to cook the curd without scrambling the eggs.
3. Stir Constantly: Cook, stirring constantly with a whisk or spatula, for about 10-15 minutes, or until the curd thickens enough to coat the back of a spoon and reaches a temperature of 170-175°F (77-79°C). It’s crucial to stir continuously to prevent the eggs from cooking unevenly and scrambling.
4. Remove from Heat and Stir in Butter: Once the curd has thickened, remove the bowl from the heat. Immediately whisk in the cubed cold butter, one piece at a time, until it is completely melted and incorporated into the curd. This will make the curd smooth, glossy, and rich.
5. Strain the Curd (Optional but Recommended): For an ultra-smooth curd, strain it through a fine-mesh sieve into a clean bowl. This will remove any cooked egg bits or lemon zest pieces, resulting in a perfectly velvety texture.
6. Cool Slightly: Let the lemon curd cool slightly for about 10-15 minutes before filling the tartlet crusts. This will prevent the curd from being too runny and soaking into the crust.

Part 3: Assembling and Baking the Lemon Curd Tartlets

1. Fill Tartlet Crusts: If you blind-baked the crusts, gently fill each pre-baked tartlet shell with the slightly cooled lemon curd, leaving a little space at the top. If you didn’t blind bake, fill the raw crusts with lemon curd.
2. Bake (If Not Blind Baked): If you are baking unbaked crusts with the curd, bake the filled tartlets in the preheated oven at 350°F (175°C) for 15-20 minutes, or until the curd is just set and no longer jiggles significantly in the center. If you blind-baked, you may only need to bake for 5-10 minutes to warm the curd and set it further.
3. Cool Completely: Remove the tartlets from the oven and let them cool completely in the tartlet pans on a wire rack. As they cool, the lemon curd will set further.
4. Chill (Optional but Recommended): For the best flavor and texture, chill the Lemon Curd Tartlets in the refrigerator for at least 2 hours before serving. Chilling allows the curd to fully set and the flavors to meld together beautifully.
5. Garnish and Serve: Before serving, you can garnish the Lemon Curd Tartlets as desired. Some popular garnishes include a dusting of powdered sugar, fresh berries (like raspberries or blueberries), whipped cream, or a sprinkle of lemon zest.