Instructions:
- Melt butter in a medium saucepan over medium heat. Add minced onion and sauté gently until translucent and soft (about 5-7 minutes).
- Add garlic and cook for one minute until fragrant—do not let it burn.
- Stir in the tomato paste. Cook it for 2 minutes, stirring constantly, to caramelise the sugars and deepen the flavour.
- Pour in the apple cider vinegar, scraping up any bits stuck to the bottom of the pan. Let it bubble rapidly for 30 seconds.
- Add water/broth, brown sugar, Worcestershire sauce, Dijon mustard, and smoked paprika. Stir well to combine. Bring the mixture to a gentle simmer.
- Lower the heat to maintain a low, steady simmer. Cook uncovered for 15–20 minutes, stirring occasionally, until the sauce thickens slightly and reduces by about one-third.
- Remove from heat. Taste the sauce and adjust salt and pepper as needed. If you prefer it thinner, add a splash more water.
- For an ultra-smooth texture, strain the sauce through a fine-mesh sieve, pressing down on the solids. Discard solids. Allow the sauce to cool completely before transferring it to an airtight container.