1. Wash banana peppers, remove stems and seeds, and chop into rough pieces. Dice the onion and peel the garlic. Wear kitchen gloves if using hot banana peppers.

2. Add all ingredients — chopped peppers, onion, garlic, white vinegar, water, sugar, salt, ground mustard, turmeric, and black pepper — to a medium saucepan.

3. Bring to a boil over medium-high heat. Once bubbling, reduce the heat to low and simmer for 15–20 minutes, until the peppers and onion are very soft and almost falling apart.

4. Remove from heat and cool for about 5 minutes, just enough so it’s safe to handle.

5. Transfer everything (liquid included) to a blender and blend until completely smooth. If the sauce is too thick, add water one tablespoon at a time. If too thin, return to the stove and simmer for another 5 minutes.

6. Pour the finished sauce into clean glass jars or bottles. Let cool completely before sealing. Refrigerate and enjoy within 2–3 weeks.