Fill a pot with water and put it on high heat.
Meanwhile, wash and carefully peel the guavas, then cut them in half.
When the water is boiling, carefully add the guavas and let them cook for 15 minutes or until they are soft.
Once cooked, remove them from the heat and discard the water. Blend the guavas for a few seconds, making sure not to disintegrate the seeds too much.
Pass this blender mixture through a strainer to extract the pulp and leave the seeds.
Place the previous mixture in a pot with the cup of orange and the sugar. Cook over low heat stirring frequently with the help of a wooden spoon to prevent the mixture from sticking to the pot.
Cook until a smooth and shiny paste begins to form. If you can see the bottom of the pot while you're stirring, it means that the mixture is ready.
The cooking may take about 1 hour.
Once ready, turn off the heat and let the mixture cool a bit.
Afterwards, you can place the paste on a tray and stretch it out to level it.
You can coat the tray with sugar before placing the mixture and sprinkle more on top of the mixture.
Let it cool for several hours and when it's compact, cut and enjoy.