Line a baking pan with parchment paper or lightly grease with olive oil.
Toss together the lemon juice, lemon zest, finely chopped broccoli florets, red pepper flakes, and a dash of salt. Broil (500F - 550F) in the oven for 5-7 minutes, until tender and crisp.
In a frying pan over medium high heat, warm up the olive oil for 1 minute. Add in the first tortilla to cook for 1-2 minutes (until golden brown spots) then flip the tortilla. Evenly spread the shredded mozzarella cheese on the tortilla, then the roasted broccoli. Cover with the second tortilla.
Cook for 2-3 minutes (until golden brown on that side), then carefully flip the quesadilla to cook an additional 2-3 minutes. Serve warm with lemon wedges and slices of avocado. Enjoy!