Preheat oven to 350ºF.
In a large bowl with an electric mixer on high speed, beat the butter and sugar until well blended.
Beat in egg, vanilla extract and lemon extract for about 30 seconds and then add in the salt and mix.
Gradually add flour, mixing until well blended.
Coat a mini muffin tin with cooking spray.
Scoop about 1 Tablespoon to 1 ½ Tablespoon of dough into each opening of the muffin tin. I use a medium size cookie scoop.
Press the dough with your thumb or a wooden tart shaper against the bottom and sides of each muffin opening. Dipping your thumb or tart shaper in flour will keep the dough from sticking.
Bake crusts 9 – 11 minutes until very baked through and slightly golden around the edges.
Remove tin from oven and cool on wire racks for 1 – 2 minutes.
Carefully remove tart crusts from the muffin tin and place the tarts on wire cooling racks to cool.