Meaty Quesadillas

Name: Meaty Quesadillas
Ingredients: 2 tablespoons extra-virgin olive oil, plus more for brushing; 3 cloves garlic, minced; 1 teaspoon ancho chili powder; 1 pound lean ground beef or lamb; 1 tablespoon finely chopped fresh oregano; Kosher salt and freshly ground pepper; 4 scallions, thinly sliced; 4 10-inch flour tortillas; 3 1/2 cups shredded muenster or monterey jack cheese; Fresh salsa and/or sour cream, for serving