Preheat the oven to 375°F (190°C). Grease a standard muffin tin with nonstick cooking spray. This recipe makes 16 mini cruffins, so you may need to bake in batches or use two muffin tins.
Make the almond filling. In a medium bowl, combine the softened butter, egg, almond flour, flour, granulated sugar, almond extract, vanilla or vanilla extract, and salt. Mix until smooth and fully combined. Set aside.
Roll out one sheet of puff pastry on a sheet of parchment paper. Spread half of the almond filling evenly over the surface.
Cut the pastry sheet in half lengthwise. Cut each long strip in half, then in half again, until you have 8 equal strips.
Roll each strip tightly into a spiral, like a snail, and place each one into a prepared muffin cup.
Repeat with the second sheet of puff pastry and the remaining almond filling.
Optional - In a small bowl, whisk together the egg and milk. Brush the tops of each cruffin with the egg wash.
Bake for 30–40 minutes, or until deeply golden brown and puffed.
Let the cruffins cool in the pan for 5–10 minutes. Remove from the pan and roll each one in granulated sugar while still warm.
Serve warm or at room temperature and enjoy.
