Heat oven to 350°F. Line two baking sheets with parchment.
Cream the butter and the dough sugar in a mixer on medium until light and fluffy, 2–3 minutes.
Beat in vanilla, almond extract, and salt until smooth.
Whisk flour, cornstarch, and ground almonds in a bowl. Add to the butter mixture on low just until a soft dough forms.
Chill the dough 15–20 minutes to firm slightly for easier rolling.
Scoop 1-tablespoon portions and roll into smooth 1-inch balls. Arrange 2 inches apart on the sheets.
Bake 12–14 minutes, until set and the bottoms are lightly golden. Do not overbrown.
Cool 5 minutes, then roll warm cookies in coating sugar. Cool completely and roll a second time for a thick finish.