Preheat your oven to 400°F (200°C).

In a large mixing bowl, combine the trimmed asparagus, sliced zucchini, and yellow squash.

In a separate bowl, whisk together olive oil, minced garlic, salt, black pepper, and red pepper flakes if using.

Drizzle the oil mixture over the vegetables and toss until evenly coated.

Spread the vegetables in a single layer on a baking sheet lined with parchment paper.

Roast the vegetables for 15-20 minutes, stirring gently halfway through.

Remove from the oven and drizzle with lemon juice and sprinkle lemon zest on top.

Toss the vegetables gently to combine without bruising them.

Top with freshly grated Parmesan cheese and serve.

Garnish with finely chopped fresh parsley before serving.