Place the garlic cloves in a small piece of foil, and wrap lightly to enclose them, but don't seal the package. Drizzle with 1-2 teaspoons olive oil. Place on the foil packet on the baking sheet and let roast for 30 minutes while you prepare the remaining vegetables.

While garlic cloves are roasting, clean, peel and trim vegetables:

Slice carrots into strips, 1/2 inch wide by 3 to 4-inches long.

Snap tough ends off asparagus.

Trim tough ends off of brussels sprouts, and cut in half if they are large.

Trim cauliflower into 2-inch florets.

Keep tomatoes whole.

Slice half the lemon into slices, and reserve the remaining half.

Place all vegetables and lemons into a large mixing bowl, and drizzle with remaining olive oil, and sprinkle with salt and pepper.

Spread vegetables onto the baking pan in a single layer, and leave packet of garlic cloves on the pan.

Increase the oven temperature to 400 degrees.

Roast vegetables and garlic for 20 minutes, or until tender, turning them occasionally, so they cook evenly.

When vegetables are tender, remove from the oven, and sprinkle thyme leaves over all. Let garlic cloves sit until cool enough to handle, and then remove the skins. Leave them whole, or gently mash.

Toss garlic and thyme with vegetables, and if desired, add an additional squeeze of fresh lemon juice.