Add dry ingredients to a food processor and pulse to mix together. Add egg whites and almond extract, then process until a ball of dough forms.
Remove from processor and roll into a log. Wrap tightly with plastic wrap and refrigerate until ready to use.
Notes
Almond paste has raw egg whites in it, but you can use the pasteurized ones from a carton to avoid any food safety issues.Refrigerate until you're ready to bake with it. Then bring to room temperature for 10-15 minutes before using. If your almond paste is too sticky, add a little more powdered sugar to the dough.