Preheat your oven to 350°F (175°C) and grease a 10-inch deep dish pie plate with butter or cooking spray.

Cook 8 ounces of dry spaghetti in salted boiling water until just shy of al dente, about 7-8 minutes, then drain and rinse under cold water.

In a mixing bowl, combine the cooled spaghetti with melted butter, Romano cheese, and beaten eggs. Press the mixture into the greased pie plate and refrigerate for 15-30 minutes.

Cook 8 slices of bacon in a skillet over medium heat until crisp, about 6-8 minutes, then chop and set aside, reserving the bacon fat.

In the same skillet with the bacon fat, sauté ½ cup of diced onions and ½ diced red bell pepper for about 3 minutes until the onions are translucent.

Add 1.5 pounds of cubed boneless chicken to the skillet, cooking until no longer pink, about 5-7 minutes.

In a separate saucepan, heat whole milk and heavy cream over medium-low heat, whisking in a little of the hot milk into the egg yolk to temper it.

Melt 2 tablespoons of butter over medium heat in a different pan, whisk in 4 tablespoons of flour to form a roux, and gradually whisk in the tempered milk mixture.

Season the roux with kosher salt, black pepper, dry mustard, and nutmeg as it thickens.

Stir in the chicken mixture, bacon bits, and shredded Fontina cheese, mixing until melted and creamy.

Spread ricotta cheese over the chilled spaghetti crust, then pour the creamy chicken mixture evenly on top.

Bake in the preheated oven for 40 minutes or until set and golden brown. Sprinkle shredded mozzarella on top and bake for an additional 5 minutes.

Switch the oven to broil for 2-3 minutes for an extra crispy top, watching closely to prevent burning.

Remove from oven, cover loosely with foil, and let rest for 20 minutes before slicing and serving warm.