Begin by halving the fresh passion fruits and scooping out the vibrant pulp along with the seeds into a mixing bowl.

In a large, heavy-bottomed pot, combine the passion fruit pulp, granulated sugar, and freshly squeezed lemon juice.

Place the pot over medium heat and bring the mixture to a rolling boil, then reduce to a simmer for 20 to 25 minutes.

Prepare for the set test by placing a small plate in the freezer, then drop a teaspoon of jam onto it to check for wrinkles.

Remove from heat, stir in a pat of butter, and fill sterilized jars, leaving 1/4 inch of headspace.

Allow jars to cool completely at room temperature before storing in a cool, dark place.