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Caramelized Onion Mushroom Apple Gruyere Bites

Caramelized onion mushroom apple Gruyere bites with crispy mini phyllo shells and jammy caramelized onions. French-inspired appetizer baked until the Gruyere melts and turns bubbly.
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Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Servings: 24 servings
Course: Appetizer, Snack
Cuisine: French-inspired
Calories: 110
Ingredients Equipment Method Notes

Ingredients
  

Onion and butter base
  • 2 tbsp butter
  • 1 yellow onion thinly sliced
  • 8 oz cremini mushrooms finely chopped
  • 1 apple small, finely diced
  • 1 tsp fresh thyme leaves
  • 1 tbsp balsamic vinegar
  • 0.25 salt and pepper to taste measure to taste
Phyllo and cheese
  • 1 box mini phyllo shells 2 boxes (15 count each); 24 used
  • 1 cup shredded Gruyere
  • fresh thyme for garnish

Equipment

  • 1 sheet pan

Method
 

Caramelize the onions
  1. Melt butter over medium-low heat; cook the onion 20-25 minutes, stirring often, until deep golden and jammy.
  2. Keep the heat at medium-low and continue cooking until the onion looks glossy, dark golden, and sticky, with most moisture cooked off.
Cook the mushroom-apple filling
  1. Add mushrooms and apple and cook 6-8 minutes, stirring, until mushrooms are browned and their liquid evaporates.
  2. Stir in thyme and balsamic, then season with salt and pepper to taste.
Fill and bake
  1. Preheat the oven to 350F and arrange the mini phyllo shells on a baking sheet.
  2. Fill each shell with the onion mixture and top with Gruyere.
  3. Bake 8-10 minutes at 350F until the cheese is melted and the shells are crisp, with bubbling around the edges.
Garnish and serve
  1. Garnish with fresh thyme and serve warm.

Notes

For the jammiest filling, cook the onions on medium-low and stir often so they caramelize instead of steaming. Store baked bites in an airtight container in the refrigerator up to 2 days; rewarm in a 350F oven for 5-7 minutes to re-crisp. Freezing is not recommended because phyllo can soften. Dietary swap: use a lactose-free shredded cheese blend in place of Gruyere for a similar melt.