Combine all ingredients in a medium stockpot. Bring to a boil over high heat, stirring frequently. Lower heat and boil gently, stirring occasionally, until mixture is thickened, about 30-45 minutes . Once the fruit has softened enough to crush easily (about 20 minutes), blend the sauce with an immersion blender, or by transferring to a blender or food processor.
When sauce has reached desired thickness (leave it a little thinner than you want, as it will thicken on cooling), taste and adjust seasonings (add any reserved chile seeds here to bump up the heat).
Ladle hot sauce into clean, hot jars, leaving 1/2-inch of headspace, and process in a boiling water bath for 15 minutes.
If you don't want to process this, it will keep in the fridge for 6-8 weeks