Guava Bars

1/2 pound butter
1 cup granulated sugar
2 egg yolks
2 cups flour
1 cup chopped nuts
1/2 bar guava paste

Cream butter. Gradually add sugar and beat until light and fluffy. Add egg yolks and beat well. Gradually add flour and mix. Fold in nuts. Spoon 1/2 of the batter into greased square pan. Top with slices of guava paste. Cover with remaining batter. Bake 1 hour at 350 degrees F until lightly browned. Cool completely before cutting.