Placed potatoes in a medium pot and fill with enough water to cover the potatoes. Boil until fork tender.
Add butter, cream, Portobello Mushroom Sauce, salt & pepper to potatoes and mash until smooth.
In a medium saute pan, heat oil over medium heat. Add onions and saute until slightly translucent. Add garlic and mushrooms and saute until tender.
Add ground beef and cook thoroughly until there is no pink remaining. Drain grease. Sprinkle with flour and then add Portobello Mushroom Sauce, peas and corn and stir to combine.
Spread beef mixture along the bottom of a 9” x 13” pan. Top with mashed potatoes.
Bake for 35 minutes, until sides are slightly bubbling and top is browned.