Toss the broccoli and cauliflower florets with olive oil, sea salt, freshly cracked black pepper, and crushed red pepper flakes, to taste, until evenly coated. Spread out into an even layer on a large baking sheet.
Roast for 15 minutes, tossing halfway through cooking time.
Mix the warm melted butter and minced garlic clove well.
Carefully pour the garlic butter over the veggies, tossing to coat evenly, then continue to roast for 1 minute.
Remove from the oven and serve immediately with fresh lemon wedges and parmesan cheese, if desired.