Preheat your oven to 325°F and line a large baking sheet with parchment paper.

Break up the almond paste into chunks and add to the food processor along with granulated sugar. Pulse until the almond paste is finely broken down and the mixture has a sandy, crumbly texture.

Add the egg white, vanilla extract, salt and orange zest. Process just until the mixture comes together into a smooth, sticky dough, scraping down the sides of the bowl as needed.

Scoop the dough into 1-tablespoon portions and gently roll into balls. I use a small cookie scoop, size #60, leveled.

Place the powdered sugar in a small bowl. Roll each ball generously in powdered sugar, then place it on the prepared baking sheet. Gently press 3 to 4 sliced almonds into the top of each cookie, taking care not to flatten the dough. Bake immediately, while the dough is still cold.

Arrange the cookies about 2 inches apart on the prepared baking sheet. Do not flatten them.

Bake for 18 to 22 minutes (20 is perfect for me), or until the cookies are crackled on top and lightly golden around the bottom edges. The centers should still be soft.

Allow the cookies to cool completely on the baking sheet before removing them from the parchment.