Step 1

Heat the oil in a large frying pan (at least 10 inches) over medium-high heat until shimmering. Add the spinach and garlic and cook, stirring often, until just wilted, about 3 minutes. Add the chili powder, season lightly with salt, and cook until all the visible liquid is evaporated, about 2 minutes more. Transfer the spinach to a fine-mesh strainer and use the back of a wooden spoon or a ladle to press out as much liquid as possible; set the spinach aside.

Step 2

Assemble the quesadillas: Place the tortillas on a work surface. Spread 1/4 cup of the beans over half of each tortilla. Divide the cheese over the beans, pressing the cheese gently into the beans. Divide the spinach over the cheese. Fold each tortilla in half so the empty side covers the filling.

Step 3

Wipe out the frying pan with paper towels and place back over medium heat until hot, about 3 minutes. Add 2 of the quesadillas and cook until golden-brown on the outside and the cheese is melted, about 3 minutes per side. Remove to a cutting board and repeat with the remaining quesadillas. Cut the quesadillas into wedges and serve with toppings.