Preheat oven to 425 degrees F.
Place a wire rack on top of a baking sheet and place the bacon on the wire rack.
Bake bacon in preheated oven for 15-20 minutes, until cooked.
Alternately, you can fry the bacon on the stovetop, but I prefer the oven method.
Cut up the bagels into small chunks. I did this with kitchen shears but you can also use a bread knife.
Place bagel chunks onto bottom of a greased 9x13” baking pan.
Sprinkle bacon and cheese on top of bagel chunks.
In a large bowl, whisk together eggs, milk, Dijon, and salt.
Pour egg mixture evenly over bagel chunks.
Evenly distribute cubes of cream cheese among the casserole.
Cover with plastic wrap and refrigerate overnight.
The next morning, take out the baking dish from the refrigerator and let it come to room temperature for about 30 minutes.
Preheat the oven to 350 degrees F.
Cover the casserole dish with aluminum foil and bake for 40 minutes.
Remove the aluminum foil and bake for an additional 10-15 minutes, until the top bagel pieces are golden brown.
Serve topped with green onions and avocado.
Enjoy!