In a Dutch oven or soup kettle, combine the first six ingredients; bring to a boil. Reduce heat; cover and simmer for 20 minutes. Add mushrooms and celery; cover and simmer for 15 minutes or until chicken and vegetables are tender.
Remove chicken and vegetables. Debone chicken; dice and set aside. Slice vegetables and set aside. Strain broth, reserving 2 cups. (Discard remaining broth or save for another use.)
Melt butter in a large saucepan; stir in flour until smooth. Gradually stir in cream and reserved broth; bring to a boil. Cook and stir for 2 minutes or until thickened and bubbly. Add the poultry seasoning, salt, pepper, peas and reserved chicken and vegetables. Pour into a 2-qt. round baking dish. Set aside and keep warm.
For biscuits, combine the flour, baking powder, sugar and salt. Cut in shortening until mixture resembles coarse crumbs. Stir in milk just until moistened. On a floured surface, roll to 1/2-in. thickness. Cut with a 2-1/2-in. biscuit cutter. Place biscuits over chicken mixture. Bake at 400° for 20 minutes or until biscuits are golden brown.