Wash and dry all produce. Preheat oven to 450 degrees. Cut potatoes into 1/2-inch cubes. Toss on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Roast in oven until browned, 20-25 minutes, tossing halfway through.

Meanwhile, halve, peel, and finely dice onion. Remove and discard stems and large ribs from collard greens. Roughly chop leaves. Heat a drizzle of olive oil in a large pan over medium heat. Add onion and cook, tossing, until softened, 4-5 minutes. Remove a quarter of the onion from pan and set aside.

Add collard greens to pan and toss. Pour in 1/4 cup water, cover pan, and cook until softened, 3-4 minutes. Uncover and toss until leaves are tender and water evaporates, another 2-3 minutes. Season with salt and pepper. Remove from pan and set aside.

Measure out 1/4 cup flour (we sent more), then set aside 1 tsp for gravy. Toss remaining flour and Cajun spice in a shallow dish. Heat a large drizzle of olive oil in same pan over medium heat. Season pork with salt and pepper, then toss in flour mixture to coat, shaking off excess. Add to pan and cook to desired doneness, 3-6 minutes per side. Remove from pan and let rest 5 minutes.

While pork rests, wipe out pan. Return pan to medium heat and add a drizzle of olive oil, reserved onion, and reserved flour. Cook, tossing, until flour loses its raw smell, 1-2 minutes. Stir in stock concentrate and 1/3 cup water. Bring to a simmer and let bubble until reduced by half, 2-3 minutes. Remove from heat and stir in sour cream. Season with salt and pepper.

Toss collard greens with potatoes on baking sheet. Return to oven and allow to warm through, 1-2 minutes. Divide between plates, then top with pork. Spoon gravy over and serve.