Bring a large pot of water to a boil. Prepare a small bowl of ice water and set aside. Cut shallow X into bottoms of each peach and place into boiling water for 1 minute. Remove to ice water until cool enough to handle. Gently remove peels and dice peaches.

In pot over medium-high heat, add peaches and onion. Cook until peaches and tomato have broken down, approximately 5 to 10 minutes. Reduce heat to medium-low. Stir in vinegar, brown sugar, salt, paprika and peppers. Cook 20-30 minutes, until mixture has reduced and sauce is thick.

Working in batches or using immersion blender, purée sauce until smooth. Pour into jars and store in the refrigerator or process in a water-bath canner for 20 minutes.