French Onion Soup Inspired Egg Rolls with Spicy Mustard

Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper for easy cleanup.

In a large skillet over medium heat, melt butter and olive oil. Add sliced onions and cook, stirring occasionally, until softened and golden brown, about 20-25 minutes. Reduce heat if onions are browning too quickly. Stir in brown sugar and balsamic vinegar during the last 5 minutes of cooking.

Remove from heat and stir in thyme, rosemary, salt, and pepper.

Place egg roll wrappers on a clean surface. Spoon about 2 tablespoons of caramelized onions and 1 tablespoon of Gruyere cheese onto the center of each wrapper.

Whisk the egg with a tablespoon of water to make the egg wash.

Fold the bottom corner of the wrapper over the filling. Fold in the sides, then roll up tightly to seal. Brush the top edge with egg wash to secure the roll.

Place egg rolls seam-side down on the prepared baking sheet. Brush the tops with egg wash.

Bake for 10-15 minutes, or until golden brown and crispy, flipping halfway through for even cooking.

While the egg rolls bake, prepare the spicy mustard dipping sauce. In a small bowl, combine spicy brown mustard, honey, and hot sauce. Adjust honey/hot sauce to your desired spice level.

Serve the crispy egg rolls immediately with the spicy mustard dipping sauce.