Slice your bread into thick slices, approximately 1.5" wide. Cut a pocket into the top of each slice, cutting into the center of the bread and out toward each side, but not all the way through the other end. You just want to form a pocket, not cut the slice in half.
In a medium sized bowl, add both cheeses, the dill weed, and salt. Set aside.
In a medium sized pan, add the olive oil and finely chopped onions. Cook over low to medium heat, stirring occasionally, until the onions are soft and translucent.
Add the minced garlic and the fresh spinach to the pan, and cook just until the spinach starts to wilt. Remove from heat.
Combine the spinach mixture with the cheese and seasonings, and stir well to create the filling.
Stuff each slice of bread with the filling.
In a bowl, add the two eggs and milk, and whisk together well.
Spray the rack or basket of your air fryer with nonstick spray.
Dip each slice of stuffed bread into the egg and milk mixture, being sure to coat both sides.
Place the slices into your air fryer, and fry at 350 degrees for about 4 minutes on each side, or until both sides are crispy and golden.