In a skillet, heat oil. Add garlic and saute for 1 minutes, until it starts to change color.
Add spinach and cook until leaves wilt. Set aside to cool for a few minutes.
In a large mixing bowl, combine cooked spinach with the corn, black beans, queso fresco and 1/4 teaspoon of the salt and black pepper. Mix to combine.
In a food processor. combine 2 cups of the tomatoes, onion, chile powder, cilantro and the rest of the salt. Puree well.
Cut off the stem end of the poblanos. Cut down the middle of the top of the pepper. Remove seeds and membranes.
Stuff peppers with the spinach filling.
Lightly spray a casserole dish with cooking spray.
Pour tomato sauce on bottom of dish. Place poblanos on top.
Top with the remaining crushed tomatoes, placing a dollop on each stuffed pepper.
Sprinkle the shredded cheese on top. Bake for 45 minutes.
Garnish with scallions and freshly chopped cilantro.
Notes
You can use different cheese if you prefer, as long as it is a good melting cheese. Other cheese options you can use are cheddar cheese, fontina or mozzarella.