Cheesy Mashed Potato and Herb Stuffed Mushrooms with Caramelized Onions Print

Most Popular, Side Dishes & Soups, Snacks & Appetizers,

Easy, Cheesy Mashed Potato and Herb Stuffed Mushrooms with Caramelized Onions and Parmesan Cheese—made with Idaho Spuds Country Buttered mashed potatoes. This beautiful, bite-size appetizer is a perfect game day crowd pleaser.

Recipe by Jessica at Coffee & Crayons

  • Prep Time

  • Cook Time

  • 18-24



  • 18-24 baby portabella mushrooms, stems removed
  • 1 Tbsp. olive oil
  • 1 Tbsp. butter
  • 1 large yellow onion, chopped
  • 2 packages Idaho Spuds Country Butter Mashed Potatoes, prepared
  • 1/2 Cup cooked wild rice (optional)
  • 1 tsp. finely chopped fresh rosemary
  • 1/2 tsp. finely chopped thyme
  • 1/2 tsp. garlic powder
  • 1 tsp. salt
  • 1/2 tsp. pepper
  • 1 Cup white cheddar cheese, shredded
  • 1/2 Cup grated parmesan cheese (plus more for topping)



  • Preheat oven to 350ºF. Line a large baking sheet with parchment paper. Prepare mushroom caps and place them on prepared baking sheet. Set aside.
  • Heat a large skillet over medium low heat. Add olive oil and butter and cook onions for 40-45 minutes, stirring occasionally, or until onions are completely caramelized.
  • While the onions are cooking, prepare the mashed potato filling. In a medium bowl mix together the prepared Idaho Spuds Country Butter mashed potatoes with the cooked wild rice, fresh thyme, rosemary, garlic powder, salt, pepper, white cheddar cheese, and parmesan cheese. Taste mixture, adding more salt and pepper as needed.
  • With a small spoon add the cheesy mashed potato mixture into the cavity of each mushroom, squeezing in as much as you can.
  • When the onions are finished caramelizing, carefully scoop a little on to the top of each mushroom cap. Place stuffed mushrooms in the oven and bake for 20 minutes. Remove from the oven and top each mushroom cap with a little extra parmesan and fresh herbs and continue to cook for an additional 15-20 minutes.