Boil chicken in water until cooked through, about 20 minutes. Remove cooked chicken from boiled water and place on a cutting board to cool. Reserve 6 to 8 cups of boiled chicken broth to be used later. Once chicken has cooled, chop or tear into bite sized pieces.
In a large stainless steel stock pot combine celery, onions and butter. Sauté on medium heat until onions are translucent, about 8 minutes. Add carrots, peas, chicken, salt, pepper and broth to the onion mixture. Bring to a boil, stirring often to avoid scorching the filling.
Take 3 cups of the reserved water from boiling the chicken, and using a whisk, whisk in Canning Gel. Add mixture to stock pot and mix well. Boil for 5 minutes, stirring often. If mixture becomes too thick, in 1 cup increments, use the reserved liquid to give the filling a thinner consistency. After filling has boiled for 5 minutes, remove from heat.
Ladle hot pie filling into hot jars being sure to leave a generous 1” headspace. Use a warm washcloth dipped in vinegar to wipe each jar rim and screw bands. Place lids and rings atop each jar and hand tighten.
Process jars in a pressure canner at 10 PSI, or according to your elevation, or according to your elevation; 75 minutes for pints and 90 minutes for quarts.
