For the sauce: Mix the ingredients until well combined.
For the Philly-Rito!: In a saute pan over medium-high heat, add the oil and onions. Cook until the onions are translucent, about 10 minutes. Add the sirloin and garlic powder and saute another 3 minutes. Fold in the cheeses to melt. Add the roasted red peppers and season with salt and pepper. Turn off the heat and set aside.
In a dry skillet, warm the tortillas 1 at a time. Hold warm under a towel. To form the Philly-Rito!, spread a spoonful of the avocado onto a tortilla, top with a quarter of the meat and roll it up like a burrito. Serve with the sour cream sauce.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.