4 poblano chiles
1-1/4 cups grated Monterey jack cheese, divided
1 tablespoon olive oil, plus some for frying
3/4 cup sour cream
2 flour tortillas, torn in quarters
1-1/2 teaspoons salt or to taste
10 corn tortillas (white-corn or other good quality)
Roast chiles over an open flame until blackened. Let cool to the touch, then (wearing rubber gloves) rinse under running water to remove skin. Seed and devein chiles and tear into several pieces. Place in a blender with 1 cup water, 1/4 cup cheese, 1 tablespoon olive oil, 1 tablespoon sour cream, and the flour tortillas and puree until smooth. Add water if necessary; sauce should be moderately thick and pourable.
Heat a small amount of olive oil in a saute pan over medium-high heat. Add the sauce and salt, reduce heat to low, and simmer, lightly bubbling, for 5 minutes.