Adjust rack to top position and preheat oven to 450 degrees. Wash and dry all produce. Peel and dice sweet potato into 1/2-inch pieces. Toss on a baking sheet with a drizzle of oil, salt, and pepper. Roast, tossing halfway through, until browned and tender, 20 minutes. Transfer to a medium bowl. Heat broiler to high or increase temperature to 500 degrees.

Meanwhile, halve, deseed, and dice poblano. Halve, peel, and dice onion. Mince a few pieces until you have 1 TBSP (2 TBSP for 4 servings). Finely chop cilantro leaves and stems. Dice tomato. Trim and quarter radishes. Quarter lime. Place 1/2 tsp Southwest Spice in a small bowl (save the rest for cooking your veggies).

Heat a drizzle of oil in a large pan over medium-high heat. Add poblano and diced onion; season with salt and pepper. Cook, stirring, until tender, 5-7 minutes. Once sweet potato is roasted, add to pan along with remaining Southwest Spice. Cook until fragrant, 1-2 minutes. Turn off heat.

In a second medium bowl, combine radishes, tomato, cilantro, minced onion, juice from 1 lime wedge (2 lime wedges for 4 servings), and large drizzle of olive oil. Season generously with salt and pepper. To bowl with reserved Southwest Spice, add sour cream, a squeeze of lime juice, and a pinch of salt. Stir in water, 1 tsp at a time, until mixture reaches a drizzling consistency.

Rub one side of each tortilla with a drizzle of oil. Place tortillas oiled sides down on baking sheet used for sweet potato. (Use 2 baking sheets for 4 servings.) Combine cheddar and mozzarella in a second small bowl. Evenly divide cheese between 1 side of each tortilla. Top with veggie mixture, then sprinkle with remaining cheese. Fold tortillas in half to create two quesadillas (four for 4 servings).

Broil or bake quesadillas until golden brown, 1-2 minutes per side. Cut quesadillas into wedges. Divide quesadillas and salsa between plates. Dollop quesadillas with crema. Serve with remaining lime wedges on the side for squeezing over.