Make a syrup by mixing sugar and water in a small pot and cook over medium to low heat until the sugar dissolves into a clear syrup While the syrup is cooking, preheat oven to 350 and add eggs to a bowl. Beat with a hand mixer or a stand mixer thoroughly at a medium speed. Add the condensed and evaporated milk to the bowl and blend further using your mixer, then add 1 tbsp of vanilla. Melt the guava paste in your microwave oven. I only needed to do 45 seconds at 100% power. Fold guava paste into beaten eggs. Mix thoroughly at medium speed. Add the two cans of milk, and mix thoroughly, then add vanilla. When your caramel is ready, pour into a 9" round baking/cake pan and move around to coat the sides evenly. Alternately, you can use muffin tins or a loaf pan. When using a muffin tin, pour the syrup into each cup one at a time and use a spatula to spread the caramel up the sides of the cups. Since the syrup is scalding and the pan can get very hot while coating, use caution doing both. Set aside and let cool.(60-90 seconds, tops). When the caramel has hardened, add beaten eggs/milk mixture to the pan or muffin tins. Cover tightly with foil paper and place into a larger pan (like a disposable aluminum roaster). Fill the larger pan with water until the water level reaches almost to the top of the baking dish. Place in oven and bake for 60 minutes. When the flan is done, run a knife along the edges of the flan to separate it from the sides of the pan. Place in the refrigerator and chill for several hours, or best, overnight When ready to serve, turn the flan onto a plate and pour the remaining caramel over it.