I would like to say that this is my favorite group in the net. Up to now almost every recipe I've tried has come out great. Here is a recipe for a guava cake. It's from El Nuevo Dia, 4/14/91, contributed by Marta Pizarro.
12 tbs butter 1 cup sugar 2 cups flour 2 eggs 1 t. baking powder 1 tsp vanilla extract 8-10 oz guava pasteProcedure
1. Preheat oven at 350F 2. Cream butter. Add sugar little by little. Add eggs one by one, followed by the vanilla 3. Sieve flour and baking powder and mix with the above 4. Pour half the batter on a greased mold. 5. Place the guava paste (cut in slices) so as to cover all the batter 6. Pour the rest of the batter and bake for 45-60 min, or until an inserted toothpick comes out clean. Notes: I have substituted butter with margarine, but the cake comes out a little more dry. The slices I cut are about 0.5 cm, but they can be even thicker depending on your taste. If you have left over guava paste you can make an easy desert by cutting slices and eating them along with cheese (in Puerto Rico we commonly use a white salty cheese) so it's not so sweet. The guava paste can be stored in the refrigerator, after opening, for several weeks.