Preheat oven to 400 degrees F.
Defrost puff pastry sheet per packaging directions. Be sure to keep the puff pastry cold.
Place the chocolate bar into a microwave safe bowl. Place in the microwave for 30 seconds. Remove and stir. Return to the oven for 15 seconds intervals, stirring in between time in the microwave, until the chocolate has melted. Set aside.
In a medium mixing bowl, add the softened butter and sugar together. Cream together using a hand mixer for 30 seconds to 1 minutes, or until smooth. Add in the eggs, vanilla extract, almond flour, almond extract, cocoa powder, and melted chocolate. Beat together until smooth.
Roll out the defrosted puff pastry sheet onto a lightly floured surface. Using a rolling pin, gently roll out the puff pastry slightly. Carefully cut into 10 squares using a knife or pizza cutter.
Place each puff pastry square into a greased muffin tin, carefully pressing the sides down to create a “cup”. Divide the chocolate almond filling into each pastry cup using an ice cream scoop or spoon. Each cup will hold roughly 1/4 cup of the chocolate almond filling. Sprinkle each chocolate puff pastry with a few almond slices if desired.
Bake in the oven for 14-16 minutes or until the puff pastry is slightly browned. Remove from the oven. Let cool slightly and enjoy!