Keep covered off heat until ready to serve.

Halve, peel, and thinly slice onion. Halve, core, and thinly slice green pepper into strips.

In a medium microwave-safe bowl, combine onion, green pepper, vinegar, ⅓ cup water, 1 TBSP sugar, and salt (⅔ cup water and 2 TBSP sugar for 8 servings).

Cover with plastic wrap; microwave until veggies are softened, 1-2 minutes.

Stir and set aside to pickle.

Heat a large drizzle of oil in a large, preferably nonstick, pan over medium-high heat. Add pork*; season with ¼ tsp salt (½ tsp for 8 servings) and pepper. Cook, breaking up meat into pieces, until cooked through, 3-4 minutes.

Add tomato paste and half the birria paste; cook, stirring, until fragrant and slightly darkened, 30-60 seconds more.

Turn off heat; transfer to a large bowl. Wipe out pan.

While filling cooks, in a second small pot, combine stock concentrates, remaining birria paste, and 1 cup water (2 cups for 8 servings) over medium heat; bring to a simmer, then reduce heat to low and cover to keep warm until ready to serve.

Place tortillas on a clean work surface. Sprinkle one half of each tortilla with mozzarella (we used one packet of cheese for every three tacos); top with pork filling. Fold tortillas in half to create tacos. 

Heat a drizzle of oil in pan used for pork filling over medium heat. Add tacos; cook until tortillas are crisped, 1-2 minutes per side. Transfer to a paper-towel-lined plate. TIP: You’ll need to work in batches. We cooked three tacos at a time.

Fluff rice with a fork; stir in chimichurri.

Divide birria broth between small serving bowls. TIP: If needed, return pot to medium heat until broth is warmed through before serving.

Divide tacos and rice between plates. Serve with pickled veggies (draining first), sour cream, and birria broth for dipping.