Preheat the oven to 450 degrees F (230 degrees C).
On a lightly floured surface, roll out the 9-inch Pie Pastry (1) to about 3/8" inch. Use the biscuit cutter to cut out rounds of dough.
Transfer the rounds to the muffin tin and place them in individual muffin wells.
Use the tamper to press the dough into place and form a mini pie shell. Bake for 5 -7 minutes or until lightly browned.
Remove from oven and cool for 5 minutes in the pan, then transfer to a wire rack to cool completely.
For the lemon curd: Zest four of the Lemon (5) and set aside. Use a citrus juicer to juice the lemons. You need half a cup of lemon juice. If you can get it from 4 lemons, great, if not, juice another lemon.
Crack the Egg (5) and separate the egg whites from egg yolks. Set aside the 5 egg yolks.
In a small saucepan, combine the Granulated Sugar (1 cup), Salt (1 pinch), lemon zest, lemon juice and egg yolks. Use a wire whisk to combine and place over medium low heat, whisking constantly and scraping the sides and bottom of the pan so it doesn't stick. Heat until the sugar dissolves and mixture begins to thicken. Remove from the heat.
Add one tablespoon of Unsalted Butter (8 tablespoon) and whisk until it completely melts and is incorporated before adding another tablespoon of butter. Continue in this manner until you've used all the butter.
Place a fine mesh strainer over a small bowl and carefully pour the lemon curd through the strainer. Use the back of a spoon or small spatula to press the curd through the strainer -- this will remove the lemon zest and any stray seeds that made it into the curd.
Cover the curd and refrigerate until chilled, about 2 hours.
Use a pastry bag or small spoon to fill the tart cups with the lemon curd.
Garnish with fresh fruit, or a dollop of whipped cream. Serve.