Crispy smashed potatoes are covered in a creamy balsamic sauce packed with caramelized onions and tender mushrooms for the ULTIMATELY easy side or appetizer!
Prick red potatoes all over with a fork and arrange on a greased baking sheet. Bake potatoes at 400F 35-40 minutes until very tender. Immediately smash potatoes flat with the bottom of a glass. Set aside.
In a medium skillet over medium-high heat, melt 2 tablespoons butter until bubbly then add onions, stirring occasionally until onions are a deep caramelized brown. Add garlic and mushrooms and saute 2-3 minutes until mushrooms are tender.
Reduce heat to medium and add balsamic vinegar, seasonings, and heavy cream. Bring to a low simmer until slightly thickened. Keep warm.
Drizzle smashed potatoes with remaining 2 tablespoons melted butter and return to oven. Broil 2-3 minutes until potatoes are a deep crispy golden brown.
Spoon mushroom sauce over potatoes and return to oven under broiler for an additional 2-3 minutes until sauce is bubby. Serve smashed potatoes hot and enjoy!