BBQ Pineapple Flatbread Pizzas

Step 1
Place 1/4 of the chopped red onion in a small bowl and add vinegar to cover. Let soak to quick-pickled, about 1 hour.

Step 2
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Cover a baking sheet with foil.

Step 3
Heat 1 teaspoon oil in a skillet over medium heat; stir in remaining onion. Cook and stir until softened and translucent, about 5 minutes. Reduce heat to low and continue cooking and stirring until onion is very tender and dark brown, about 40 minutes more. Add pineapple and cook until heated through, 2 to 3 minutes. Remove from heat.

Step 4
While onion is cooking, place green pepper cut-sides down onto the prepared baking sheet. Broil until the skin of the peppers has blackened and blistered, 5 to 8 minutes. Remove from the oven, turn off the broiler, and preheat the oven to 450 degrees F (230 degrees C).

Step 5
Place blackened peppers into a bowl and cover tightly with plastic wrap. Replace the aluminum foil with a fresh sheet. Allow peppers to steam as they cool, about 20 minutes. Remove and discard skins and chop into bite-sized pieces.

Step 6
Brush both sides of each flatbread with the remaining olive oil and place on the prepared baking sheet. Brush with barbeque sauce and top with onion-pineapple mixture, roasted peppers, Monterey Jack cheese, mozzarella cheese, and cilantro.

Step 7
Bake in the preheated oven until crust is crispy and cheese is melted, 10 to 12 minutes.