Pulse blueberries, vinegar, and sugar in a food processor or blender until chunky.

Transfer blueberry mixture to a saucepan. Add bay leaf, cinnamon stick, garlic powder, and crushed red pepper. Simmer covered 10–15 minutes. Remove from heat and discard bay leaf and cinnamon.

Transfer to a blender until smooth, then strain into a bowl using a mesh sieve. Return to saucepan and simmer uncovered on low to medium low until reduced by ¼ (about 20-25 minutes), until syrupy and coats a spoon. Cool completely and store in the refrigerator (makes ~3 cups and keeps up to 6 months refrigerated).

Preheat the oven to 275 degrees. Remove any membrane from the back of the ribs. Then, add the mustard and evenly spread on each of the slabs of ribs. Next, season the ribs on both sides with all of the spice rub. Using your fingertips to press the rub into the ribs so that it sticks.

Wrap the ribs tightly with foil (double wrap if you need to, as you dont want the ribs to leak), meat side up, and place on a parchment lined baking sheet. Bake the ribs for 2 1/2 to 3 hours or until the ribs are tender and a sharp knife can easily pierce the meat.

Once the ribs are fully cooked, remove them from the foil and place them on a parchment lined baking sheet. Turn your oven to high broil.

Liberally brush the ribs with the blueberry barbecue sauce until fully covered (if the sauce is too thick, warm it slightly so it thins out before brushing). Place the ribs in the oven and broil on high for 1–2 minutes, until the sauce is lightly caramelized. Remove from the oven and baste again (this is my favorite step because I love extra saucy ribs — but you can skip the second baste if you prefer). Return the ribs to the oven and broil for another 4–8 minutes (or 5–10 minutes total if only doing one baste), until the sauce is bubbly, caramelized, and has great color with a little char. Watch closely so they don’t burn. Remove from the oven and serve immediately.