Step 1Heat the oil in a small skillet over medium-high heat and fry the tortillas about 1 minute on each side. Drain on paper towels.
Step 2Cook the onion over medium heat, using the same pan, just long enough to remove the raw flavor, about 3 minutes.
Step 3Heat the oven to 350 degrees.
Step 4Begin your assembly of the enchilada stack by dipping a fried tortilla, using tongs or your fingers, into the red chile sauce. Lay it in a 2 1/2-quart shallow casserole. Spread a layer of 2 tablespoons of onion, 1/4 cup of grated cheese and some olives. Keep dipping, stacking and layering ingredients until you have used all of the tortillas. Try to keep the layers even and then press the stack from the top middle so everything adheres together. Pour any remaining sauce around the base of the stack.
Step 5Bake the stack until the cheese has melted and started to bubble, 15 minutes.
Step 6Just before serving, drizzle leftover heated red chile sauce (about 1/2 cup) over the sides of the pie and garnish with abandon by drizzling crema over the top so it spills down the sides. Sprinkle on the crumbled queso fresco.
Step 7Toss the romaine with the olive oil, salt and wine vinegar. Arrange the romaine ribbons around the base of the stack with a little on top. Garnish further with avocado slices. Serve immediately by cutting the stack into 4 to 6 wedges. Make sure that each wedge has enough of the crumbled cheese, the romaine and avocado slices.