Preheat oven to 425 degrees.
Cut broccoli and cauliflower into large florets. Peel and thinly slice garlic cloves. Cut lemon in half and then into thin slices.
On a parchment paper-lined baking sheet toss broccoli, cauliflower, garlic cloves and lemon together with extra virgin olive oil. Coat evenly. Season generously with salt and pepper.
Roast in preheated oven for 35 minutes or until the floret edges begin to brown and curl.
Remove from the oven and give everything another good toss before serving. Enjoy!