1. Finely chop 1 tablespoon garlic. Trim scallions, then thinly slice.

2. Heat 1½ tablespoons oil in a large skillet over medium-high until shimmering. Add corn and cook until browned in spots, 2–3 minutes. Transfer to a small bowl. Heat 1½ tablespoons oil in same skillet over medium-high. Add beef, taco seasoning, and a pinch each of salt and pepper. Cook, breaking up meat into small pieces, until browned, 4-5 minutes.

3. Carefully pour off any fat. Stir in chopped garlic, half of the scallions, and 2 tablespoons flour. Cook, stirring, until garlic is fragrant, about 30 seconds. Stir in 1 cup water and cook until liquid is reduced by half, 1–2 minutes. Stir in corn; season to taste with salt and pepper. Remove from heat.

4. Preheat broiler with top rack 6 inches from heat source. Brush 1 side of 8 of the tortillas (save rest) generously with oil, then arrange tortillas on a work surface, oiled sides down. Divide beef-corn mixture among tortillas, then top each with cheddar. Fold into half-moons to close.

5. Broil quesadillas on top oven rack until cheese is melted and tortillas are golden brown, rotating baking sheet and flipping quesadillas halfway through for even browning, 2–4 minutes total (watch closely as broilers vary). Let stand for 5 minutes. Cut quesadillas into wedges and garnish with remaining scallions.