Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Peel and dice sweet potato into 1/2-inch pieces. Core, deseed, and dice green pepper into 1/2-inch pieces. Halve, peel, and cut onion into 1/2-inch-thick wedges; thinly slice 2 wedges (4 wedges for 4 servings). Finely chop cilantro leaves and stems.

Toss sweet potato, green pepper, and onion wedges on a baking sheet with a drizzle of oil and a big pinch of salt and pepper. Roast on top rack, tossing halfway through, until browned and tender, 20-25 minutes.

Meanwhile, in a small pot, combine rice, 3/4 cup water (11/2 cups for 4 servings), and a big pinch of salt. Bring to a boil, then cover and reduce to a low simmer. Cook until rice is tender, 15-18 minutes. Keep covered off heat until ready to serve. While rice cooks, toss sliced onion in a small bowl with vinegar, 1 tsp sugar (2 tsp for 4), and salt. Set aside, stirring occasionally, until ready to serve.

In a second small bowl, combine sour cream, half the Southwest Spice (you’ll use the rest later), 1/4 tsp chipotle powder (we sent more), and a big pinch of salt. Add water 1 tsp at a time until mixture reaches a drizzling consistency. Taste and add more chipotle powder if desired.

Pat steak dry with paper towels; season with salt, pepper, and remaining Southwest Spice. Heat a drizzle of oil in a large, preferably ovenproof, pan over medium-high heat. Add steak; cook until browned but not yet cooked through, 2-3 minutes per side. Transfer pan to oven. (TIP: If your pan isn’t ovenproof, add steak to sheet with veggies, pushing veggies to one side.) Roast to desired doneness, 5-7 minutes. Transfer to a cutting board.

Fluff rice with a fork; stir in 1 TBSP butter (2 TBSP for 4 servings), salt, and pepper. Divide between bowls. Thinly slice steak against the grain. Top rice with sliced steak, roasted veggies, pickled onion, crema, and cilantro. Serve.