Wash and dry all produce. Adjust rack to middle position and preheat oven to 450 degrees. Line a baking sheet with aluminum foil and lightly oil. Halve potatoes lengthwise, then cut into 1/2-inch-thick wedges (like steak fries). Trim, then thinly slice scallions, separating greens and whites.

In a small bowl, stir together sour cream, mayonnaise, mustard, and 2 TBSP vinegar (we’ll use the rest in step 5). Season with salt and pepper and stir to combine.

In a medium bowl, mix together beef, panko, scallion whites, stock concentrate, 2 tsp barbecue seasoning (we’ll use more later), pepper, and salt (we used 2 tsp kosher salt). Shape mixture into four loaves, each about 1-2 inches tall and 3-4 inches long.

Toss potatoes with a large drizzle of olive oil. Season with another 2 tsp barbecue seasoning (save the rest for step 6) and plenty of salt and pepper. Spread out in a single layer on your lined baking sheet. Add meatloaves to same sheet. Bake in oven until potatoes are crisp and meatloaves are cooked through, about 25 minutes.

Meanwhile, place cabbage and remaining vinegar in another medium bowl and toss to coat. Season with salt and pepper. Set aside to marinate, tossing occasionally. About 5 minutes before meatloaves are done, add half the scallion greens to same bowl along with just enough sauce to lightly coat the cabbage (2-4 tsp). Toss to coat. Season with salt and pepper.

Divide cabbage, potatoes, and meatloaves between plates. Stir remaining barbecue seasoning into sauce. Spoon a little sauce over meatloaves and sprinkle with remaining scallion greens. Serve any remaining sauce on the side for drizzling over or dipping the potatoes into.