Preheat oven 350F.
Preheat a large skillet over high heat with 3 tablespoons of EVOO then add the mushrooms and saut until golden. Add onion, garlic, jalapeo, salt and ground black pepper, and saut until softened and slightly caramelized.
While the veggies are cooking, make the dipping sauce: In a food processor, puree avocado, 1 cup cilantro, lime juice, sour cream and hot sauce and salt to taste. Pour into a serving bowl and reserve.
Over an open flame of a gas burner or a hot grill, lightly char each side of all 14 tortillas and reserve on a plate.
In a small bowl, add the beans and mix in remaining 1/2 cup chopped cilantro, salt and ground black pepper, and reserve.
Once the veggies are done, add them to the food processor bowl the dipping sauce was pureed in. Add the cheese and process to a slightly chunky paste.
On a clean, flat, work surface, lay 6 tortillas out and spread cheese mixture on 3 of them. On the other 3, spread refried beans. Stack them up, topping with a plain tortilla, so you have a 7-layer stack. Repeat with the remaining tortillas, alternating the filling the same way as before and topping with a plain tortilla.
Preheat a skillet over medium low heat with a tablespoon of EVOO and place one stack into the skillet. Cook until brown on each side, about 3 minutes. When the first 7-layer stack is done, pop it into the oven to stay warm while you brown the other.
To serve, gently cut each Mile-High Quesadilla into wedges using a serrated knife, and serve with the avocado dipping sauce alongside.