1) In a large pot, combine chicken, celery stalk and 1/2 yellow onion. Cover with 1 litre cold water. Simmer until the chicken is tender and cooked through, about 40 minutes.
2) Remove chicken from cooking liquid to cool on cutting board. Once cool shred, discarding the skin, bones and fat.
3) Combine chicken meat with half of the white salsa and set aside.
4) In a large skillet, heat 1 tablespoon corn oil over medium high heat. Add onions, red peppers and broccoli. Saute until onions are soft, about 3 minutes. Add corn and cook for another 5 minutes. Season with salt and pepper. Transfer to a bowl and mix with half of the roasted red salsa.
5) Heat 4 tablespoons vegetable oil in medium skillet over medium-high heat. Add a tortilla and lightly fry for 10 to 15 seconds. Flip the tortilla over and continue to fry until the tortilla is pliable and heated through, about another 10 to 20 seconds. Place tortillas on a paper towel lined plate, cover with a kitchen towel, and set aside. Repeat with the remaining tortillas.
6) Preheat oven to 200c/Gas 6.
7) Place four tortillas on a baking sheet. Top each with a layer of the chicken mixture. Top chicken mixture with another tortilla, then a layer of vegetable mix. Top with another tortilla. Spread the remaining white salsa on the top tortilla of each of the 4 towers. Sprinkle with the Mexican cheese blend and bake for 5 minutes or until cheese starts to brown. Remove from oven and transfer to a serving plate.
Garnish with coriander and serve with remaining roasted red salsa.
Roasted red salsa:
1) Preheat oven to 200C/Gas 6.
2) Rub the tomato, onion, garlic head and poblano pepper with 1 tablespoon corn oil and place them on a foil lined baking sheet. Roast for 20 minutes or until the tomato and pepper skins start to blacken.
3) Remove to cutting board to cool. Squeeze garlic to release from its skin. Quarter the onion. Remove the stems and seed from the poblano pepper.
4) Combine all the roasted vegetables in a blender and blend for 1 minute, or until smooth.
5) Heat remaining 1 tablespoon corn oil in a medium saucepan over medium-high heat. Add the tomato mixture, sugar, oregano, salt and pepper. Cover and cook for 6 minutes. Set aside.
Heat cream cheese and double cream in a medium saucepan over medium-low heat until cheese begins to melt. Cook for 5 minutes, stirring occasionally, or until the mixture is completely smooth. Season with salt and pepper.