Bring a pot of water to boil and add potatoes, boil until potatoes start to get tender

Add your broccoli, cauliflower and carrot and boil for another 3 minutes

Drain the water from the pot

Heat butter in a pan and add garlic. Sauté until garlic soften

Add the potatoes, carrots, cauliflower and mushroom to the garlic butter sauce and give everything a stir to coat with the butter and garlic sauce