Wash and dry produce. Dice tomato into ½-inch pieces. Trim and thinly slice scallions, separating whites from greens. Quarter lime. Halve, peel, and thinly slice onion. Halve, core, and thinly slice green bell pepper into strips.

In a small bowl, combine tomato, scallion greens, and juice from half the lime. Season with kosher salt and black pepper.
In a separate small bowl, combine 5 TBSP sour cream (for 2 servings) and a pinch of Southwest Spice Blend (you'll use the rest later). Add water 1 tsp at a time until mixture reaches drizzling consistency.

Pat 10 oz steak dry with paper towels; thinly slice against the grain. Season all over with remaining Southwest Spice Blend, salt, and pepper.

Heat a drizzle of cooking oil in a large pan over medium-high heat. Add steak, onion, green bell pepper, and scallion whites. Cook, stirring occasionally, until veggies are tender and steak is cooked to desired doneness, about 3-6 minutes.

Wrap flour tortillas in damp paper towels and microwave until warm and pliable, about 30 seconds.

Divide tortillas between plates. Fill with steak and fajita veggies. Top with 1/2 cup Monterey Jack, pico de gallo (draining first), and spiced crema. Serve with remaining lime wedges on the side.