This easy-to-make Stuffed Mushrooms with Duck Heart Recipe uses bell pepper, onion, spinach, panko breadcrumbs, and asiago cheese. Enjoy these duck heart delights as an appetizer or serve them as a nutritious and filling main course.
Place the duck hearts on a cutting board and trim off and discard the thin white ring of fat you'll find at the top of each one. Transfer the trimmed duck hearts to a medium mixing bowl.
To the mixing bowl, add the liquid aminos, 1 tablespoon of minced garlic, and 1 tablespoon of olive oil. Stir well to combine and marinate the duck hearts in the refrigerator for 15 minutes.
Preheat the oven to 400 degrees F and line a baking sheet with aluminum foil or parchment paper.
Meanwhile, clean the portobello mushrooms by wiping the top surfaces with a damp paper towel to remove any dirt. Then flip them over, pull out the stem (if there is one). I don't mind eating the interior gills, but if you want to remove them grab a soup spoon from your kitchen drawer. Use this spoon to scrape away the interior gills and discard. Place the mushrooms open side up on the parchment-lined baking sheet and coat the outer sides and edges of the mushrooms with about 1 tablespoon of olive oil per mushroom. Place them in the preheated oven to bake for 10 minutes.
While the mushrooms are baking in the oven, cook the duck hearts. Place a skillet over medium-high heat, add the marinated duck hearts, diced onion, and diced red bell pepper and sauté for 1 minute, stirring constantly. Then transfer the duck heart mixture to a medium size bowl and add all the remaining ingredients for the filling, including the remaining 1 tablespoon of minced garlic and 2 tablespoons of olive oil. Mix well to combine.
When the mushrooms are done cooking in the oven for 10 minutes, remove them from the oven and stuff each one with the filling. Return the stuffed mushrooms to the oven and bake another 15 minutes.