Prepare the Tart Crust:

1. Prepare the Tart Shells:

   • In a large mixing bowl, combine the cold, cubed butter, flour, powdered sugar, and salt. Using a pastry blender, two forks, or your fingers, mix the ingredients until the mixture resembles coarse crumbs.

   • Add the egg yolk and 1 tablespoon of ice water. Mix gently until the dough starts to come together. If the dough feels dry, add another tablespoon of ice water and continue mixing until it forms a dough.

   • Gather the dough into a ball, wrap it in plastic wrap, and chill in the fridge for 30 minutes.

2. Roll Out the Dough:

   • After chilling, lightly flour your work surface and roll out the dough to about ¼ inch thick. Use a round cookie cutter or a glass to cut circles that are slightly larger than your mini tart pans.

3. Press Into Tart Pans:

   • Gently press the dough circles into the bottom and sides of mini tart pans or a muffin tin, making sure to create an even thickness. Prick the bottom of the tart shells with a fork to prevent them from puffing up while baking.

4. Chill the Tart Shells:

   • Place the tart pans back in the fridge for an additional 10-15 minutes. This step ensures the crust holds its shape during baking.

5. Bake the Tart Crusts:

   • Preheat your oven to 350°F (175°C). Bake the tart shells for about 15-20 minutes, or until golden brown. Remove them from the oven and allow them to cool completely before filling.

Prepare the Lemon Curd Filling:

1. Make the Curd Base:

   • In a medium heatproof bowl, whisk together the eggs and sugar until smooth. Stir in the lemon juice, lemon zest, and a pinch of salt.

2. Cook the Curd:

   • Set the bowl over a pot of simmering water (double boiler method), making sure the bottom of the bowl doesn’t touch the water. Cook the mixture, whisking constantly, for about 10-12 minutes until it thickens and coats the back of a spoon.

3. Finish the Curd:

   • Once thickened, remove the curd from the heat. Stir in the cubed butter, a little at a time, until fully incorporated. Continue to whisk until smooth and glossy.

4. Cool the Curd:

   • Allow the lemon curd to cool to room temperature. If you want a smoother texture, you can strain the curd through a fine mesh sieve to remove any lemon zest or egg bits.

Assemble the Mini Tarts:

1. Fill the Tart Shells:

   • Spoon the cooled lemon curd into the baked tart shells, filling them up nearly to the top. Smooth the tops with a spoon or offset spatula to ensure an even layer of curd.

2. Chill the Tarts:

   • Refrigerate the tarts for at least 2 hours, or until the lemon curd has fully set and the tarts are chilled.

Garnish and Serve:

1. Add Toppings:

   • If desired, top the mini tarts with fresh berries, a dollop of whipped cream, or a mint leaf for added flavor and decoration.

2. Serve:

   • Once garnished, serve the tarts chilled or at room temperature. These mini tarts are perfect for any occasion and will surely be a crowd favorite.