Preheat oven to 400℉. Spray a 9 x 13-inch baking dish with nonstick cooking spray and set aside.
In small bowl, mix the poppy seeds, sesame seeds, minced garlic and minced onion. Reserve 1 teaspoon of mixture and set all aside.
In a small bowl mix the mayonnaise and Dijon mustard.
Pat chicken dry. Sprinkle both sides of chicken with salt and pepper and place in the prepared dish.
Brush top side of chicken with the mayonnaise mixture. Sprinkle each breast with Everything but the Bagel seasoning, reserving the teaspoon for the cream cheese sauce.
Bake in 400℉ for about 30 minutes or until a meat thermometer reaches 160℉ in the thickest part of breasts.
Meanwhile, in a medium bowl, melt butter in microwave. Add cream cheese and return to the microwave for a few seconds. Remove from microwave and whisk. Add the heavy cream, reserved Everything but the Bagel seasoning and green onions.
When chicken is baked, remove from oven and let stand 5 minutes. Serve with cream cheese sauce.