Sweet Almond Pastry: First sift the flour with the almond meal, confectioners sugar, baking powder, and salt. Place in the bowl of your electric stand mixer, fitted with the paddle attachment. (Can also use a hand mixer). Add the chunks of cold butter and beat on medium low speed until the mixture is mealy (grainy with no visible pieces of butter). Add the cold egg yolks and seeds from the vanilla bean (if using) and beat on low speed until the dough comes together (pastry will be yellow in color).

Place the pastry onto your work surface and gather into a ball. Divide the pastry into 6 equal pieces (about 60 grams each). Wrap each piece of pastry in plastic wrap. Place in the refrigerator to chill for at least six hours (the pastry can be stored in the refrigerator for up to three days or frozen for up to three months). After the pastry has chilled sufficiently, place on a lightly floured surface, and roll each piece into a 5 1/2 inch (14 cm) round. (To prevent the pastry from sticking to the counter and to ensure uniform thickness, keep lifting up and turning the pastry a quarter turn as you roll.) Place the rounds of pastry on a baking sheet, cover, and chill in the refrigerator for about 15-30 minutes (to firm up the pastry which makes it easier to place in the tart rings). Then gently place each round into a 4 x 3/4 inch (10 x 2 cm) tart ring (or tart pan). Never pull the pastry or you will get shrinkage (shrinkage is caused by too much pulling of the pastry when placing it in the tart pan). Gently lay in pan and lightly press the pastry onto the bottom and up the sides of the tart ring. With a sharp knife cut excess pastry from top of tart ring. Then with a thumb up movement, again press dough into creases of ring. Place the tart rings on a parchment lined baking sheet, cover, and place in the refrigerator while you preheat your oven.

Preheat your oven to 350 degrees F (180 degrees C).

Lightly prick the bottom of each pastry crust with the tines of a fork (this will prevent the dough from puffing up as it bakes). Line each unbaked pastry shell with parchment paper or aluminum foil. Fill each tart ring with pie weights or beans, making sure the weights are to the top of the ring and evenly distributed over the entire surface. Bake for about 20 to 25 minutes until crust is dry and lightly browned. Place on a wire rack. Remove the paper and weights and let the tart shells cool.

Key Lime Filling: In the bowl of your electric mixer, fitted with the whisk attachment, (or with a hand mixer) beat the egg yolks until pale and fluffy (about 2 minutes). Gradually add the condensed milk and beat until light and fluffy (about 2 minutes). Scrape down the sides and bottom of the bowl and then beat in the lime juice and zest. 

Fill each tart shell about 3/4 full with the filling and bake for about 10 - 15 minutes, or until the filling is just set (the center of the filling will still look a little wet). Remove from oven and place on a wire rack to cool. Once they have completely cooled, refrigerate for several hours or overnight.

Whipped Cream: Once the tarts have chilled, in the bowl of your electric mixer, fitted with the whisk attachment (or with a hand mixer), beat the whipping cream and sugar until stiff peaks form. Either pipe or place mounds of whipping cream on top of the filling. Can be stored in the refrigerator for a 2-3 days.

Makes 6 - 4 inch (10 cm) tarts