Preheat oven to 350°F/175°C/Gas Mark 4.

Heat oil in large skillet on med/high and add onions (if using fresh jalapeños, add them at this time). Cook for a few minutes or until starting to turn translucent and tender. Add minced garlic and continue to cook for one more minute.

Stir flour and sour cream together in a bowl until fully blended without lumps, then add this mixture to the skillet.

Continue to cook and stir this mixture for at least 1-2 minutes to cook the flour that will be used to thicken this white sauce (It’s kinda like making a roux – we want to cook the flour to get the flour taste out).

Pour in the chicken stock, green chilies and all seasonings for the white sauce. Cook until thickened a bit and bubbly.

Remove from heat, reserve 1 cup of this sauce and set aside. Stir in the cooked chicken and the cheese until cheese has melted. Warm tortillas in microwave for 15-20 seconds to make them more pliable if needed.

Divide filling among the 8 tortillas. Place some of the red enchilada sauce on the bottom of a 12” x 8” x 2” (or similar size) oven safe dish and spread around a bit. This will help prevent the enchiladas from sticking to the bottom of the dish.

Roll up the filled tortillas and place them seam side down in the dish and top with the reserved white sauce. No need to cover them edge to edge, just cover at least two thirds of the enchiladas, then repeat with 1 cup of the red enchilada sauce.

Uncover, top with the remaining cup of cheese and bake for another 5 minutes or until cheese has melted.

Garnish with chopped tomatoes and green onions. Let rest for 5-10 minutes before serving.