Dice onion and water saute onions over medium high heat until they are soft and slightly caramelized.
While onion is cooking, slice carrots then add carrots and continue to cook till carrots are slightly softened.
While carrots are cooking mince garlic and slice mushrooms, then add to pot along with the remaining ingredients.
Cover pot. Once stew is simmering, reduce heat and simmer until carrots are soft.
Serve over linguine or mashed potatoes.