Make the ancho sauce ahead of time.
Preheat oven to 400 degrees F.
Mix cheddar, Monterrey Jack and green peppers in a medium bowl.
Heat ancho sauce in sauce pan, or in microwave-safe bowl. Remove from heat and set aside.
Heat oil in medium sized, non-stick skillet.
Once oil is hot...quickly add a corn tortilla to the skillet...flip every few seconds, for a total of about 20 seconds...should start to crisp up. Quickly add into the ancho sauce.
Flip the tortilla to cover with sauce. Hold up with tongs, to let excess fall off tortilla.
Add prepared tortilla to baking dish. Add 3 tablespoons of cheese/pepper mixture.
Fold tortillas, so the edges cross on top.
Continue with remaining tortillas and filling.
Top with a good drizzling of the ancho sauce.
Top with about a tablespoon of finely diced onions.
Bake for about 12 minutes...until cheese is melted and good and bubbly.
Remove...gently add to serving plates (This takes a steady hand, and using two metal spatulas at once helps. Enchiladas are fragile when transferring to platter or plate).
Garnish with cilantro and diced tomato.
Serve with sour cream and restaurant style salsa