Make the BBQ Beef Base: Heat a skillet over medium. Add olive oil or butter, then sauté onion for 3–4 minutes until softened.
Stir in garlic for 30 seconds. Add leftover ground beef, breaking up any clumps. Pour in BBQ sauce, vinegar, and smoked paprika.
Simmer 3–5 minutes until hot and glossy. Season with salt and pepper. Keep warm.
Loaded BBQ Beef Baked Potatoes: Preheat oven to 425°F (220°C).
Pierce potatoes with a fork, rub with a little oil and salt, and bake 45–60 minutes until tender, or microwave 7–10 minutes, flipping halfway.
Split potatoes, fluff with a fork, and add butter, salt, and pepper. Spoon hot BBQ beef over each potato. Top with cheese, sour cream, green onions, and jalapeños if using.
BBQ Beef Flatbreads: Preheat oven to 450°F (230°C) or heat a grill to medium-high.
Place flatbreads on a sheet pan.
Spread a thin layer of BBQ sauce, sprinkle half the cheese, add BBQ beef, red onion, and the rest of the cheese.
Bake 8–10 minutes (or grill 4–6 minutes) until edges are crisp and cheese melts. Finish with a drizzle of BBQ sauce and chopped cilantro or parsley.
BBQ Beef Stuffed Peppers: Lower oven to 400°F (205°C). Toss pepper halves with a little olive oil, salt, and pepper.
Place cut-side up on a baking dish.
In a bowl, mix warm BBQ beef with cooked rice or quinoa and corn. Spoon into peppers and top with cheese.
Cover with foil and bake 20 minutes. Uncover and bake 10–15 minutes more, until peppers are tender and cheese is bubbly.