In a large bowl, mix butter and sugar. Add egg, flour, almond extract, and almond flour. Spread mixture over pastry.
Slice apples ⅛-inch thick. Arrange them in a circular pattern on top of almond mixture.
Fold dough over so that it covers the filling by 2 inches. Brush galette with agave and sprinkle cinnamon on top. Bake at 400°F for 20 minutes. Cool, slice and serve.