Preheat the oven to 400°F (204°C).
In a large mixing bowl, combine the grated almond paste, grated frozen butter, and flour. Toss to mix until it looks like coarse crumbs.
Chill the bowl with the mixture for 10 minutes.
Make a well in the center and pour in the chilled buttermilk and almond extract (if using). Add sugar if desired.
Stir gently until a sticky dough forms—do not overmix.
Turn the dough onto a lightly floured surface and pat into a ¾-inch thick disc.
Fold and gently roll the dough 4–5 times to create layers and flakes.
Using a biscuit cutter, cut out biscuits and place them on a parchment-lined baking sheet or in a cast iron skillet.
Bake for 12 minutes then flip them then leave for an additional 3 minutes until the tops are golden brown.
While warm, brush the biscuits with melted butter mixed with almond extract.
Sprinkle sliced almonds on top for extra crunch and almond flavor.