Sour Cream

1. Place the round beef roast in the freezer for 20–30 minutes to firm slightly for easier slicing. 2. Using a sharp knife, slice the beef as thinly as possible against the grain. Thin slices ensure tenderness during quick cooking. 3. Toss sliced beef with olive oil and salt. Let sit 15–30 minutes at room temperature to lightly marinate. 4. Slice onions and bell peppers into thin strips. 5. Heat a large skillet over medium-high heat until very hot. 6. Add a small drizzle of olive oil if needed. Add peppers and onions first. Cook 4–6 minutes, stirring occasionally, until softened and lightly charred at the edges. Remove and set aside. 7. Add sliced beef in a single layer (work in batches to avoid overcrowding). Sear 1–2 minutes per side until browned but not overcooked. Beef should reach at least 145°F for medium and remain tender. 8. Return peppers and onions to the skillet and toss briefly with the beef. 9. Warm tortillas in a dry skillet for 20–30 seconds per side until soft and pliable. 10. Fill each tortilla with steak and pepper mixture. Top with shredded cheddar cheese and a spoonful of sour cream. 11. Finish with a squeeze of fresh lime before serving.