Mix the sauce base. In a bowl, whisk BBQ sauce, broth, Worcestershire, vinegar, brown sugar or honey, smoked paprika, garlic powder, and hot sauce if using.
The broth thins the sauce so it coats evenly in the crockpot.
Load the crockpot. Add frozen meatballs to a 4- to 6-quart slow cooker. Pour the sauce over and stir to coat. If using homemade raw meatballs, see the Common Mistakes section for safety tips.
Cook low and slow. Cover and cook on Low for 4–6 hours or High for 2–3 hours, until heated through and tender.
Stir once midway if you can to prevent sticking and ensure even glazing.
Make the slaw. In a bowl, whisk mayo or yogurt, vinegar, sugar, a pinch of salt, and pepper. Toss with shredded cabbage until lightly coated. Taste and adjust for tang and sweetness.
Chill until serving.
Quick-pickle the onions. Toss thinly sliced red onion with vinegar, a pinch of sugar, and salt. Let sit 10–15 minutes to soften and brighten.
Cook your base. Make rice, cauliflower rice, or quinoa according to package directions. Fluff and keep warm.
Finish the sauce. If you want a thicker glaze, remove the lid for the last 20–30 minutes on High to reduce.
Alternatively, stir in a slurry of 1 teaspoon cornstarch mixed with 1 tablespoon water and cook 5–10 minutes until glossy.
Assemble the bowls. Spoon rice into bowls. Top with a generous scoop of BBQ meatballs and extra sauce. Add slaw, quick onions, and your favorite toppings.
A squeeze of lime brightens everything.
Serve. Garnish with green onions, cilantro or parsley, sesame seeds, and jalapeños if you like heat. Keep extra BBQ sauce on the table.