1 c heavy cream
1/2 c milk
1 lb. guavas
1/2 - 3/4 c sugar
Remove the blossom ends from the guavas and give them a good rinse. Puree in a food processor then run the fruit through a mesh strainer to remove the seeds and skin. This should yield about 1 c of pulp.
Whisk the heavy cream, milk, fruit pulp and sugar together thoroughly. Start with a 1/2 c of sugar then add a bit more if needed. Pour into molds and freeze until set. Unmold by running under water briefly then gently sliding the paletas out.
If you have any of the mixture left pour the rest off into your ice cream maker (and follow manufacturer instructions for ice cream) or into a shallow dish. Freeze and stir every hour to break up the ice crystals.