In a medium bowl, rub together sugar and zests using your fingertips until sugar turns a pale orange shade. Whisk in almond flour until well combined.

In a large bowl using a hand mixer, beat egg whites until medium peaks form. Add in almond extract, amaretto, and almond flour mixture and fold to combine. Store dough in an airtight container for at least 2 hours, up to overnight.

When ready to bake, preheat oven to 325°. Line a baking sheet with parchment.

Portion dough into balls about 1 tablespoonful each. Roll in more granulated sugar before placing on prepared sheet 2 apart.

Bake until bottoms are lightly golden, about 23 to 25 minutes.