Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 450 degrees. Wash and dry produce.

Dice tomato. Roughly chop cilantro. Halve and peel onion; thinly slice one half. Finely chop remaining onion until you have 2 TBSP. Quarter lime. Halve, core, and thinly slice bell pepper into strips.

In a medium bowl, combine tomato, cilantro, chopped onion, juice from half the lime, and a pinch of salt and pepper.

In a small bowl, combine sour cream with as much hot sauce as you like. Stir in water 1 tsp at a time until mixture reaches a drizzling consistency. Season with salt.

Heat a drizzle of olive oil in a large pan over medium-high heat. Add beef*, Southwest Spice Blend, chili powder, and a few big pinches of salt. Cook, breaking up meat into pieces, until browned, 4-5 minutes (it’ll finish cooking in the next step).

Once beef is browned, add bell pepper, sliced onion, and a pinch of salt to pan. Cook, stirring, until veggies are tender and beef is cooked through, 5-7 minutes.

Add stock concentrate and ¼ cup water (½ cup water for 4 servings). Simmer until thickened, 1-2 minutes. Season with salt; remove pan from heat and set aside.

Drizzle tortillas with 1 TBSP olive oil (2 TBSP for 4 servings); brush or rub to coat all over. Arrange on a baking sheet in a single layer (divide between two sheets for 4). Gently prick each tortilla in a few places with a fork.

Bake on top rack, flipping halfway through, until lightly golden, 4-5 minutes per side. (For 4, bake on top and middle racks; flip tortillas and swap rack positions halfway through baking.) TIP: Watch carefully—tortillas brown fast!

Divide tortillas between plates; evenly sprinkle with Mexican cheese blend. Top with beef mixture, salsa, and crema. Serve with remaining lime wedges on the side.