Blanch and prepare the heirloom tomatoes by boiling them for 3-5 minutes, then plunge into an ice bath to cool. Peel, seed, and chop them.

Combine prepared heirloom tomatoes, diced peaches, sugar, apple cider vinegar, ginger, red pepper flakes, salt, and black pepper in a medium saucepan over medium heat, stirring gently.

Bring the mixture to a vigorous boil, reduce heat to medium-low and let it simmer for about 1 hour, stirring occasionally until thick and glossy.

Once thickened, remove from heat and stir in fresh basil, adjusting seasoning as desired.

Cool the jam in the saucepan for about 15-20 minutes, then transfer to a 1-pint mason jar and refrigerate.