Preheat your oven to 375°F (190°C).
In a small skillet over medium heat, add the extra virgin olive oil followed by the diced red onion and minced garlic, sautéing until they are soft and fragrant.
Stir in the tomato puree, ancho chili powder, ground cumin, sea salt, and black pepper, then simmer the sauce for 5 minutes to let the flavors develop.
In a medium mixing bowl, combine the shredded cooked chicken breast with 2 tablespoons of the warm ancho chili sauce to keep the protein moist.
Briefly warm the corn tortillas in a dry pan for 30 seconds per side until they become soft and pliable.
Place a portion of the chicken mixture into the center of each tortilla, roll them up tightly, and arrange them seam-side down in a small baking dish.
Pour the remaining ancho chili sauce evenly over the top of the tortillas and sprinkle with the shredded sharp cheddar cheese.
Bake for 12 to 15 minutes until the cheese is completely melted and the sauce is bubbling at the edges.
Remove from the oven and garnish with freshly chopped cilantro before serving hot.