About the hot pepper flakes. Double the amount for medium heat, and triple it for hot.
Method
1) Put the oil into a quart sauce pan, and warm it on a medium-low heat. Add the onion and sweet red peppers and sweat them until the onions are limp. Add the garlic and cook it for about a minute.
2) Add the dry ingredients except the sugar. Cook, stirring, for about 3 minutes in order to develop and extract their flavors.
3) Add the remaining ingredients and mix thoroughly. Bring to a low boil for 3 minutes, stirring frequently to keep the sugar from burning or sticking to the bottom. Simmer on low for another 15 minutes
Using bottled lemon juice instead of freshly squeezed fruit introduces a flat, metallic acidity that dulls the bright punch necessary to balance one cup of dark brown sugar. Fresh citrus supplies volatile oils in the zest and pure malic acid that structural vinegar alone cannot replicate. Small batch condiments demand deliberate technique, especially when heavy sugars are involved.
Sweating Aromatics Without Browning
Finely mincing onions and sweet red peppers to a uniform size ensures they soften simultaneously in the vegetable oil over medium-low heat. Cook the mixture until the onions turn completely limp, signaling that the cellular walls have broken down and released their moisture. Garlic requires precise timing here, needing only about a minute of heat to eliminate its raw bite without scorching into bitterness, which would ruin the entire batch.
Blooming Spices in Fat
Toasting dry ingredients such as ground celery seed, black pepper, and thyme in the warm oil for three minutes extracts fat-soluble aromatic compounds. This blooming phase forces the spices to release their essential oils directly into the pan before any liquids enter. Skipping this step leaves the spices tasting raw and powdery rather than fully integrated into the condiment base.
Managing Sugar and Simmering Times
Incorporating dark brown sugar alongside prepared dijon-style mustard creates a dense mixture prone to scorching. Maintain a low boil for three minutes while stirring constantly with a heat-resistant spatula to prevent the sugars from caramelizing too deeply against the bottom of the saucepan. Drop the heat to a simmer for an additional fifteen minutes to meld the vinegar, pepper flakes, and tomato paste into a cohesive consistency.