Preheat the oven to 375 °F (190 C)
Line a sheet pan with aluminum foil or parchment paper.
Clean the mushrooms and remove the stems and place caps on the baking sheet.
Slice off the dried bottom of each of the stems and discard.
Finely chop the remaining stem pieces (by hand or in a chopper)
In a skillet, fry the bacon until crispy.
Remove the bacon, chop it and return it to the pan.
Add the canola oil to the pan along with the chopped stems, minced onion and garlic.
Over medium heat, saute until cooked through. (About 5 minutes) and then remove from the heat.
Add the softened cream cheese to a mixing bowl.
Stir in the egg white, salt, pepper and onion powder and mix well.
Pour in the sauteed mushroom stems mixture from the pan and stir.
Stir in 1 cup of the grated cheddar cheese. Reserve the remaining cheese for topping the mushrooms.
Combine until thoroughly mixed.
Divide the filling between the 16 mushroom caps, making sure the filling is packed into each mushroom.
Divide the remaining shredded cheddar cheese between the stuffed mushroom caps.
Bake in the oven for 25 minutes. (you should see a melted cheese top and a small amount of liquid under the baked mushroom.)
Remove from the oven and cool for a few minutes before serving.