Raspberry Poppy Seed Cookies

7 cups confectioners' sugar
7 cups unsalted butter, softened
2 tablespoons plus 1 teaspoon vanilla extract
7 eggs
3 3/4 pounds all-purpose flour
1 1/3 cups poppy seeds
1 1/4 tablespoons salt
3 1/2 cups raspberry preserves

Heat oven to 300 degrees F.

Beat confectioners' sugar and butter with an electric mixer until light and fluffy. Add vanilla extract and egg. Blend well. Stir in flour, poppy seeds and salt until thoroughly combined. Drop dough by rounded teaspoonsful 1 inch apart onto ungreased cookie sheets. Make an indentation in center of each cookie. Fill each with about 1/2 teaspoon preserves.

Bake for 20-25 minutes, or until golden brown. Remove immediately from cookie sheets.