Fry the bacon in a skillet over medium heat until crisp. Remove to a paper towel-lined plate and pour off the excess grease.
Return the skillet to the stove over high heat. Add a couple tablespoons of butter. When it's melted and the skillet is hot, add the onions, bell peppers and jalapenos. Stir the veggies around and cook until starting to soften and turn golden brown.
Meanwhile, mix together the half-and-half, eggs and some salt and pepper in a bowl. Pour the egg mixture into the skillet with the veggies. Scoot the eggs around the skillet with a spatula, cooking slowly, until the eggs are done. Turn off the heat and set aside.
To assemble the quesadillas, set a griddle or skillet over medium-low heat and add some butter. Toss together the grated Cheddar and Monterey Jack in a bowl. Put a tortilla on the griddle and add a layer of cheese, a layer of the cooked eggs and veggies, a layer of bacon slices, a layer of avocado if using and another layer of cheese. Top with a second tortilla. Cook on both sides, flipping carefully, until the cheeses are totally melted and the filling is hot. Repeat with the other tortillas and ingredients.
Slice the 3 quesadillas into 4 wedges each. Serve on a plate with sour cream and pico de gallo or salsa (or grab them and head out the door!).
This recipe makes 3 quesadillas, which should serve 6 people.