Packets of Vanillina available HERE! Jars of Preserve available HERE! Preheat your oven to 350F degrees. Line a baking sheet with parchment paper. In a food processor add the almonds an process until fine, about 1 minute. Remove to a mixing bowl and add the sugar, zest, vanilla and egg whites. Mix with your hands until all the egg whites are absorbed. Divide the dough into balls about the size of a rounded tablespoon and place them 2 inches apart on the baking sheet. Using your finger make an indentation on each cookie and fill the indentations with jam. Bake for 10-15 minutes or until the bottoms are slightly browned. Cool completely before serving.