Preheat oven to 375°F. 

Cream butter and sugar using an electric mixer. Add egg yolks, lemon peel (if desired), vanilla extract, almond extract and salt; beat until smooth and fluffy.

Mix in flour and ¼ cup almonds, stirring just until blended. Gather into a ball; cover and refrigerate 1 hour. 

Lightly coat a baking sheet with non-stick spray or line with baking paper.

Shape dough to form 1-inch balls; roll into remaining 1 cup almonds to coat lightly.

Place 2 inches apart on baking sheet. Using your thumb or a wooden spoon handle, make a depression in each cookie.

Fill each with scant ½ teaspoon preserves. Bake in a 375°F oven for 20 to 25 minutes or until golden brown.

Cool on baking sheet 5 minutes; sprinkle with confectioners sugar, if desired. Transfer to wire racks; cool completely. Store in airtight container.

*To roast chopped almonds, spread in an ungreased baking pan. Place in 350°F oven and bake 5 to 6 minutes or until golden brown and fragrant; stir once or twice to assure even browning. Note that almonds will continue to roast slightly after removing from oven. 

Source: Almond Board of California