In a large pot, combine the diced mangoes and chopped pineapple. Cook over medium heat, stirring occasionally, until the fruits begin to break down and release their juices. This helps form the jam's flavorful base and softens the fruit for the next steps.

Add the granulated sugar to the softened fruits in the pot. Stir continuously until the sugar is fully dissolved. This sweetens the mixture and starts to form the jam's syrupy consistency.

Bring the fruit and sugar mixture to a boil. Then reduce the heat and allow it to simmer, stirring occasionally to prevent sticking. Let the mixture cook until it noticeably thickens, intensifying the flavors.

Once your jam has thickened, stir in the fresh lemon juice and minced red chili. Mix thoroughly to evenly distribute the chili throughout the jam. For a delightful kick, adjust the amount of chili to taste. I always taste at this point—sometimes I like a little extra chili for added heat!

If you prefer a thicker, more traditional jam texture, stir in the pectin now. Simmer for an additional 10 minutes to allow the pectin to activate and set the mixture.

To check your jam's set, place a small amount on a cold spoon; if it gels after a minute, it's ready. Remove the pot from heat and let the jam cool slightly. Transfer the jam into sterilized jars, seal tightly, and store in a cool, dark place. For best results, let the flavors develop for a day or two before enjoying.