Prepare the aromatics: Heat olive oil in a medium saucepan over medium heat. Add the chopped red onion and minced garlic, sauteing until softened and fragrant (about 3-4 minutes).

Add the blueberries and bourbon: Stir in the blueberries and bourbon. Cook for about 5 minutes, allowing the blueberries to soften and the bourbon to reduce slightly.

Add remaining ingredients: Mix in ketchup, apple cider vinegar, brown sugar, maple syrup or honey, Worcestershire sauce, molasses, smoked paprika, chili powder, cayenne pepper (if using), salt, allspice, and black pepper.

Simmer: Bring the mixture to a gentle boil, then reduce heat to low and let it simmer uncovered for about 15 minutes. Stir occasionally until the sauce thickens and the flavours meld together.

Blend (optional): For a smooth sauce, use an immersion blender directly in the pan or transfer the sauce to a blender and puree until smooth. For a chunkier texture, skip this step.

Taste and adjust: Taste the sauce and add more salt, spice, or sweetness if needed.

Cool and store: Let the sauce cool to room temperature. Store in an airtight container in the refrigerator for up to 2 weeks.