Warm the olive oil in a large skillet over medium-high heat until it glistens.
Add the sliced carrots and chopped onion pieces, letting them cook for about 5 to 7 minutes, stirring here and there until they soften.
Toss in the bell pepper strips, broccoli, cauliflower, mushrooms, and zucchini. Continue cooking for an additional 6 to 8 minutes, turning occasionally to allow the veggies to brown lightly and become tender-crisp. For firmer zucchini, introduce it in the last three minutes instead.
Lower the heat to medium-low. Move the cooked vegetables to the edges of the skillet to clear the center space. Add the butter and allow it to melt.
Stir in the minced garlic into the melted butter and cook for roughly 1 minute until it becomes aromatic.
Combine all the vegetables and garlic-butter mixture, remove from heat, and season with sea salt and black pepper to taste. Gently stir until the butter is fully mixed in.
Finish by sprinkling fresh parsley on top if you like, and serve warm.