In a heavy-bottomed pot, heat olive oil over medium heat. Add ground beef and a pinch of salt. Thoroughly crumble the beef as it browns.

Once the beef is browned and crumbled, add onions, garlic, and a pinch of salt. Cook until the onions become translucent.

Stir in chili powder, paprika, ground cumin, chili flakes, and dried oregano. Cook for 20-30 seconds until fragrant.

Add chicken stock, tomato sauce, brown sugar, apple cider vinegar, and a pinch of salt. Bring to a simmer and cook for 15 minutes until thickened. Taste and adjust salt if necessary.

Meanwhile, prepare the taco sauce (BRI-TEGA): soften dried guajillo chiles removing stems and seeds, boil water, turn off heat, and place chiles in the water to soften for about 15 min.

In a blender, combine tomato sauce, softened guajillo chiles, water, sugar, paprika, garlic powder, cumin, oregano, onion powder, salt, and apple cider vinegar. Blend until very smooth.

Preheat the oven to 185°F (85°C). Keep a sheet tray inside to keep taco shells warm.

Shred the romaine lettuce finely and grate the pepper jack and sharp cheddar cheese.

To fry the taco shells, fill a 4-quart saucepan about ⅔-¾ full with neutral oil and heat to 325°F (163°C). Use taco frying tongs to fry each corn tortilla for about 90 seconds until lightly golden brown. Transfer to the oven to keep warm.

Once the taco shells are ready, assemble the tacos by filling each shell with a quarter cup of the taco meat mixture, a pinch of the cheese blend, a generous drizzle of BRI-TEGA sauce, shredded lettuce, and diced fresh tomatoes. Add sour cream and raw onions if you’d like.