Preheat the oven to 350°F
Grease an 8x8x2-inch baking dish. Line with parchment paper and allow the ends to hang on the sides.
In a bowl, cream butter and sugar until light and fluffy
In a separate bowl, use a whip to mix the almond, coconut flour, salt, and baking powder.
Incorporate the flour mixture into the butter mixture.
Alternate adding one egg at a time and the coconut milk mixed with almond and vanilla.
Spoon half of the batter into the baking dish. Use an offset spatula to move the batter in the pan to ensure evenness.
Take the guava paste slices and place them over the batter. The paste will not melt and spread, so keep this in mind while placing them over the batter. An alternative for the paste could be a guava preserve or jam.
Cover the guava with the other half of the cake batter. Again, use the offset spatula to ensure the batter has been spread evenly throughout the pan.
Bake for 22 to 25 minutes or until a toothpick or a fork comes out clean. Let the cake cool. Unmold and cut into bars, about 12 to 16 pieces depending on your liking.