Mushroom Chicken Chimichangas

Preheat the oven to 400 degrees Fahrenheit (200 degrees Celsius). Line a heavy baking sheet with parchment paper or a silicone baking mat to prevent sticking and make cleanup easier.

Heat 1.5 teaspoons of vegetable oil in a large, heavy skillet over high heat. Sear the onion, poblano peppers, and mushrooms in the hot oil, sprinkling with salt, until they become tender and release their natural juices, taking about 5 minutes. Continue cooking until the vegetables start to develop a rich brown color, which may take anywhere from 5 to 10 minutes.

Transfer the cooked vegetables to one side of the skillet, leaving a small gap in the center. Drizzle an additional 1.5 teaspoons of vegetable oil into the empty space. Add chicken breast pieces to the center of the skillet and sprinkle with salt, cumin, ground chipotle, and dried Mexican oregano. Cook and stir until the chicken pieces develop a nice brown color on both sides, which should take about 5 minutes.

Combine the chicken and vegetable mixture in the skillet; remove from heat. Drizzle a small amount of water over the chicken mixture and scrape off any browned bits from the bottom of the pan using a wooden spoon. Transfer the mixture to a bowl and let it cool down to a warm temperature.

Mix pepperjack cheese into the chicken mixture; stir until thoroughly combined. Season with salt, black pepper, and cayenne pepper to taste.

Place a large skillet over medium heat. When the pan is hot, warm a tortilla in the skillet for about 30 seconds on each side.

Place the warmed tortilla onto a work surface and spoon one-quarter of the filling into the center of the tortilla. Fold the bottom half of the tortilla just over the filling, then brush the top and exposed parts of the inside with egg white. Fold in both sides towards the center, like an envelope, to enclose the filling. Roll the tortilla into a rectangular packet by rolling it over onto itself fully. Repeat with the remaining tortillas and filling.

Heat 2 tablespoons of vegetable oil in a large skillet over medium heat. Sear the chimichangas on both sides in the hot oil until they're golden brown, taking about 2 to 3 minutes per side. Transfer the cooked chimichangas to a prepared baking sheet.

Bake the chimichangas in the preheated oven until they're puffed up, golden brown, and crispy on the outside, taking about 12 to 15 minutes. Top each chimichanga with a spoonful of guacamole, sour cream, salsa, and cilantro.