Adapted from Domesticate Me
Heat 2 tablespoons olive oil in a large non-stick pan and when hot, add the onions and sauté for about until lightly browned and soft.
Add the Brussels sprouts to the pan and the stock and continue cooking until all of the liquid has evaporated and the onions are beautifully glazed.
Add the balsamic and cook for one Now assemble your quesadillas by placing sliced brie as evenly as possible on one half of each tortilla and top the brie with onion brussels sprout mixture then fold the tortillas over.more minute. Remove from the heat.
Heat your pan or cast iron skillet. When hot, add your quesadillas one by one and cook for about three minutes on each side until the tortilla is lightly browned and crisp and the cheese has fully melted.
Cut in to triangles and serve immediately.