On a baking sheet, broil tomatillos, onion, garlic, and serrano peppers for 8 to 10 minutes. Transfer the roasted vegetables to a blender. Add cumin, cilantro, chicken stock, flour and salt to blender, and purée until smooth.
Heat olive oil in a large skillet. Pour in blended mixture, taking care not to splatter, and bring to a boil. Lower heat and simmer until thickened, about 6 to 8 minutes.
Cut corn tortillas into quarters. In a large skillet heat remaining oil and fry corn tortilla pieces until crunchy. Lower heat to low. Add sauce and mix only long enough to coat all the tortillas.
Top with shredded Oaxaca cheese while over low heat and cook just long enough for cheese to melt. Remove from heat and sprinkle with onions.
Serve with eggs cooked any style and top with crumbled queso fresco. Pair with 8-ounce glass of milk and enjoy!
490 calories; 21 g fat; 7 g saturated fat; 165 mg cholesterol; 26 g protein; 52 g carbohydrates; 6 g fiber; 470 mg sodium; 674 mg calcium. Nutrition figures based on using fat-free milk, and include an 8-ounce glass of milk. Nutrition figures may vary based on egg preparation method.