Preheat oven to 350 degrees. Place chicken breasts in baking dish and cover with 1/3 cup buffalo sauce (reserve remaining) and celery, brush sauce over the tops to coat. Place in oven and bake 25 minutes or until cooked through (time varies depending on size of chicken).
Remove from oven and shred chicken. Add remaining 1/3 cup of buffalo sauce and stir to coat. Set aside.
In a medium sauce pot over medium heat, add butter and melt. Add garlic and stir to cook- about 30 seconds. Add flour and stir for 30 seconds. Slowly add milk/cream in about 1/3 cup increments, whisking between each addition. Bring to a boil, whisking constantly. Reduce heat and simmer for 20 seconds.
Add cream cheese, bleu cheese, mozzarella cheese, salt, and pepper and whisk until cheese are melted through. Remove from heat and set aside.
In a medium bowl, add ricotta, green onions, celery, egg, and ranch seasoning (optional); stir to combine completely. Set aside.
Begin by pouring a bit of cheese sauce on the bottom of the Lasagnera, then top with noodles. Add 1/3 of the ricotta mixture and spread across noodles. Top with 1/2 buffalo chicken, 1/3 mozzarella cheese, and then 1/3 of the remaining cheese sauce. Top with noodles and repeat layers once more.
For the 3rd layer (3rd set of noodles), top noodles with remaining cheese sauce and mozzarella cheese. Cover loosely with foil.
Place in preheated oven (350 degrees) and bake for 60 minutes. Remove foil and bake 10 more minutes. Remove from oven.
Top with garnishes: buffalo sauce and green onions. Slice and serve!