Step 1: Boil tomatoes in water for 15 minutes; cool, peel, and blend with onion, garlic, cumin, and peppercorns.
Step 2: Blend with 1 cup of stock until smooth.
Step 3: Heat olive oil in a stockpot; add the sauce and cook for 2 minutes.
Step 4: Add remaining stock, season with salt, simmer for 5 minutes until slightly thickened.
Step 5: Turn off heat, add oregano, mix, and drizzle over crispy tacos, flautas, sopes, or tostadas.