Preheat oven to 350°. Cream butter, brown sugar and salt until light and fluffy. Beat in vanilla. Gradually beat in flour. Press onto bottom of a greased 15x10x1-in. baking pan. Spread with preserves.
In another bowl, beat almond paste and sugar on low speed until blended. Beat in vanilla and eggs, one at a time. Pour over preserves.
Bake 20-25 minutes or until a toothpick inserted in almond layer comes out clean. Cool slightly on a wire rack.
Meanwhile, place chocolate in a large bowl. In a small saucepan, bring cream just to a boil; pour over chocolate. Stir with a whisk until smooth. Add confectioners' sugar, butter and vanilla; beat until smooth.
Spread over warm bars. Cool completely before cutting.