Start by rinsing 2 poblano peppers. Roast the poblanos in the oven for 25-30 minutes at 400F.
If you are building the Avocado Salsa Verde, you can also roast 4 tomatillos in the same pan as the poblanos. But remember that the tomatillos will need less time roasting. Take them out when they start to turn army green, approx 10-15 minutes.
Add the roasted tomatillos to a blender along with 1/2 onion, 1 garlic clove, 10-12 sprigs cilantro, and 1/2 of a serrano pepper (or 1/2 of a jalapeno pepper). Pulse blend and taste for heat, adding the additional 1/2 of the serrano (or jalapeno) if you want more heat. Add the avocado to the blender and combine well. Salt to taste.
Once the poblanos have roasted, let them cool and then pull off any loose bits of skin, but don't worry about getting rid of every last piece.
De-stem and de-seed the poblanos, cutting them into thin, bite-sized strips.
Saute 1/2 an onion in a dollop of oil over medium heat. When the onion is tender (4-6 minutes) add the poblano strips along with a generous pinch of salt and some freshly ground pepper. Let this mixture saute for a few minutes.
Heat up a wide skillet over medium heat. Warm up the tortillas before building the quesadillas (I usually give them 30-60 seconds in the skillet right before building).
Each quesadilla gets a layer of refried beans, cheese, poblano-onion mixture, cilantro, and cheese. Fill only half of the tortilla so you can fold it onto itself.
Cook the quesadillas for 2-3 minutes per side or until the cheese is melted and they start to turn golden brown.
Serve immediately.