Get your oven going at 375°F (190°C) and lightly grease a baking dish. I usually use a 9×13 pan for this just enough room to snugly line up those enchiladas.
Heat that olive oil in a skillet over medium heat. Toss in the chopped onion and garlic, and sauté until they’re soft and smelling amazing (about 3-4 minutes).
Add in the black beans, rice, corn, cumin, chili powder, salt, and pepper. Stir it all together until it looks like a cozy little Tex-Mex party in your pan.
Once it’s all warmed through and mixed, remove from heat and stir in the ½ cup of shredded cheese. This is the good stuff that holds it all together.
Spoon 2-3 tablespoons of filling into the center of each tortilla. Roll them up snugly, like you’re tucking in a sleepy burrito baby, and place them seam-side down in your prepared baking dish.
In a small bowl, mix your marinara sauce with oregano and cayenne (if you’re using it). Pour it evenly over the enchiladas. Trust the process the marinara works beautifully here and gives you a mellow, flavorful base.
Sprinkle the remaining 1 cup of cheese over the top. Yes, all of it. Don’t skimp now.
Pop the dish in the oven and bake for 20-25 minutes, until the cheese is melted and bubbly and you’re tempted to stick your face directly in the pan (please don’t, though).
Let it cool just slightly (enough so you don’t burn the roof of your mouth again), then go wild with your toppings:Fresh cilantro for brightnessAvocado slices for that creamy goodnessQueso fresco or a dollop of Greek yogurt for tangLime wedges on the sideA few chili slices if your people like a little heat You can serve these up as-is, or add a simple side salad, some tortilla chips, or even a pitcher of margaritas if you’re feeling festive.