Step 1

Place the bell peppers directly over a gas flame. Char on all sides until the skin burns, 3 to 5 minutes. Refrigerate them to cool quickly, 5 to 10 minutes.

Step 2

Place the peppers on a flat surface. Remove the top core and open the pepper up so it lies flat on the cutting board, charred skin-side up. Use a kitchen towel to wipe the charred skin away. Remove the seeds and slice the peppers lengthwise into 1/2-inch slices.

Step 3

Heat 2 tablespoons olive oil in a large saute pan over medium heat until it begins to smoke lightly. Add the zucchini, then sprinkle with salt and cook until tender and lightly browned, 3 to 5 minutes. Transfer to a bowl or baking sheet to cool.

Step 4

Add 2 tablespoons olive oil to the same pan where you cooked the zucchini, followed by the scallions and garlic. Sprinkle with a pinch of salt and cook over medium heat until they become tender, 2 to 3 minutes. Add the tomatoes and chili powder and cook until the tomatoes break down a little, 5 to 8 minutes. Stir in the black beans and vinegar and cook, gently pressing on the beans with the back of a spoon to crush and mix with the tomatoes, until the vinegar cooks down, 2 to 3 minutes. Taste for seasoning. Transfer to a bowl and allow to cool for about 30 minutes.

Step 5

Arrange 6 tortillas on a baking sheet and spread each with about 2 tablespoons of the bean mixture. Drain any moisture from the peppers and zucchini and gently press them both on top of the black bean mixture to make it all stick together, then top with the cheese. Press the remaining 6 tortillas on top of the filling. Top with another baking sheet and gently press down to flatten the filling and make the quesadillas sturdy. Refrigerate for at least 30 minutes and up to overnight.

Step 6

Preheat the oven to 200 degrees F.

Step 7

Heat a grill pan or large nonstick skillet over medium-high heat. Add 1 tablespoon oil and heat until it smokes lightly. Add 2 quesadillas, side-by-side, and brown on the first side, 2 to 3 minutes. Use a metal spatula to flip them on their second side. Add about another tablespoon of oil and cook until browned around the edges, an additional 2 to 3 minutes. Transfer to a sheet tray. Repeat with the remaining quesadillas in batches of 2, keeping the cooked quesadillas warm in the oven.

Step 8

On a flat surface, cut each quesadilla into quarters and arrange on individual plates or a large serving platter. Top with the sour cream, sliced cayenne pepper and cilantro leaves.