Set out your cream cheese to soften while you prep the mushrooms.
Remove the stems from all the mushrooms. I do this by getting my thumb way down in there and twisting. Discard the stems.
Wash your mushrooms. Brush them clean if you like to waste time and/or eat dirt. I mean it's not going to kill you. But washing them is a lot faster and won't affect your mushrooms at all.
Lay the mushroom caps top-down in a 9x13 inch casserole dish.
In a medium bowl, beat or stir the cream cheese and egg yolk until it is smooth.
Add the blue cheese, green onion, crumbled bacon, garlic, salt, and pepper. Stir to combine.
Spoon the mixture into each mushroom cap and distribute evenly.
In a glass measuring cup, stir together about 2/3 cup blue cheese dressing with 1/3 cup hot sauce (or whatever ratio tastes good to you).
Drizzle the sauce over the mushrooms.
Bake at 375 for about 20 minutes, or until the tops start to brown. Eat with a fork!
Notes
*For the sauce, you can use whatever ratio of dressing to hot sauce you want. If you like it really spicy, add more. If you like it more mild, add less.Source: The Food Charlatan