Wash all vegetables. Peel the carrot if desired. Cut everything into similar-sized pieces so they cook evenly. This prep takes about 5 minutes.

Heat a large 12-inch skillet over medium-high heat and add the olive oil. Let it warm for about 30 seconds until it shimmers and moves easily across the pan but doesn't smoke.

Add the minced garlic and sliced onions to the hot oil. Sauté for 1 to 2 minutes, stirring frequently to prevent the garlic from burning. You'll smell the garlic become fragrant and see the onions start to soften and turn translucent at the edges.

Add the carrots and broccoli florets first, since these denser vegetables need more time. Cook for 3 to 4 minutes, stirring often to ensure even cooking and prevent sticking.

Toss in the bell peppers, zucchini, mushrooms, and snap peas. Sauté for another 5 to 6 minutes, stirring occasionally. The vegetables should be crisp-tender with bright colors. If your pan looks crowded and vegetables are steaming instead of sautéing, cook in two batches.

Season with salt and black pepper to taste. If using, add lemon juice or balsamic vinegar and toss everything together. Remove from heat immediately to prevent overcooking.

Transfer to a serving dish and garnish with your choice of toppings. Serve while hot for the best texture and flavor.