Adjust rack to top position and preheat oven to 450 degrees. Wash and dry all produce. Halve and peel onion. Thinly slice one half; finely dice remaining. Core, deseed, and thinly slice poblano. Dice potatoes into 1/2-inch pieces. Quarter lime. Drain corn.

Toss potatoes on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Roast on top rack, tossing halfway through, until browned and tender, 20-25 minutes.

Meanwhile, heat a drizzle of olive oil in a large pan over medium heat. Add sliced onion and poblano and cook, stirring, until lightly browned and tender, 6-7 minutes. Add half the corn (all for 4 servings) and cook, stirring, until warmed through, 2-3 minutes more. Season with salt and pepper. Transfer veggies to a large bowl; cover to keep warm.

Pat steak dry with paper towels; season all over with salt and pepper. Heat a drizzle of olive oil in same pan over medium-high heat. Add steak and cook to desired doneness, 3-6 minutes per side. Set aside on a cutting board to rest.

Heat a drizzle of olive oil in pan used for steak over medium heat. Add diced onion and cook, stirring, until softened, 2-3 minutes. Stir in 1/8 tsp chipotle powder (we sent more) and cook until fragrant, 20-30 seconds. Stir in 1/4 cup water (1/3 cup for 4 servings) and stock concentrate. Let simmer until reduced by half, 2-3 minutes. Remove from heat; stir in sour cream. TIP: If you like things spicy, add more chipotle powder to taste.

Thinly slice steak against the grain. Add potatoes and a squeeze of lime juice to bowl with veggies; toss to combine, then divide between plates. Top veggies with steak and drizzle steak with sauce. Serve with remaining lime wedges on the side.