Preheat your oven to 400°F (200°C).

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

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

Drizzle the seasoned olive oil mixture over the vegetables and toss to coat evenly.

Line a baking sheet with parchment paper and spread the coated vegetables in a single layer.

Roast the vegetables in the preheated oven for 15-20 minutes, tossing halfway through.

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

Serve the roasted vegetables on a dish topped with grated Parmesan cheese and chopped parsley.