Make 1 cup dry brown rice according to package instructions. Fluff and set aside.
In a large skillet, heat olive oil over medium. Add diced onion and a pinch of salt; cook 5–6 minutes until soft and lightly golden. Stir in garlic for 30 seconds.
Add tomato paste, cumin, chili powder, and smoked paprika. Cook 1 minute, stirring, until fragrant and the paste darkens slightly.
Stir in black beans and corn. Pour in broth, simmer 3–4 minutes until thick but saucy. Season with salt and pepper. Off heat, add lime juice and cilantro.
In a large bowl, mix the bean-corn mixture with the cooked rice. Taste and adjust seasoning. It should be slightly salty and bold—freezing mutes flavors.
Microwave the stack wrapped in a damp towel for 30–45 seconds, or toast briefly in a dry skillet. Warm tortillas don't crack, which is kind of the whole point.
Lay a tortilla flat. Add about 3/4 cup filling just below the center. Top with 1/4 cup shredded cheese. Fold sides in, roll tightly from the bottom, and tuck as you go. Repeat.
For A+ texture, sear burritos seam-side down in a lightly oiled skillet 1–2 minutes per side until lightly golden. This helps “seal” the seam and adds flavor.
Let burritos cool to room temp before freezing. Steam = soggy tortillas. Patience now saves sadness later.
Wrap each burrito tightly in foil or parchment, then place in a freezer bag or airtight container. Label with date and contents.