• Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. • Cut potatoes into 1/2-inch-thick wedges. Halve, peel, and thinly slice onion; mince a few slices until you have 1 tsp (2 tsp for 4 servings). Peel and mince garlic. Mince cilantro. Finely dice jalapeño, removing ribs and seeds for less heat. Zest and quarter lime.

• Toss potatoes on a baking sheet with a large drizzle of oil, half the Southwest Spice (you’ll use the rest later), salt, and pepper. • Roast on top rack until browned and crispy, 20-25 minutes.

• While potatoes roast, heat a large drizzle of oil in a medium, preferably nonstick, pan over medium-high heat. Add sliced onion; cook, stirring occasionally, until browned and softened, 8-10 minutes. • Add 1 tsp sugar (2 tsp for 4 servings) and a splash of water; cook until caramelized, 2-3 minutes more. Season with salt and pepper. Turn off heat.

• Meanwhile, in a small bowl, combine sour cream, cilantro, minced onion, lime zest, 1/4 tsp garlic, juice from 2 lime wedges (4 wedges for 4 servings), a pinch of jalapeño, a pinch of cumin, 1 TBSP olive oil (2 TBSP for 4), salt, and pepper. • Halve buns; toast in oven until golden, 3-5 minutes. TIP: Place directly on oven rack, or use a second baking sheet.

• Halve grilling cheese crosswise into two squares. Place on a plate and season all over with remaining Southwest Spice. • Heat a drizzle of oil in a large, preferably nonstick, pan over medium-high heat. Add grilling cheese and cook until browned, 1-3 minutes per side.

• Divide toasted buns between plates; fill with caramelized onion, grilling cheese, and creamy chimichurri. Serve with potato wedges and remaining lime wedges on the side.