In a large mixing bowl, cream sugar & butter. Add eggs, one at a time, beating well. Add vanilla.
Combine the flour, baking powder, & salt; add to creamed mixture alternately with milk. Beat just until combined.
Fold in pecans.
Pour into three greased 9" round baking pans. Bake at 350°F for 25-30 minutes. Cool for 10 minutes before removing from pans; set aside & cool completely.
For frosting, beat the cream cheese, butter, powdered sugar, & vanilla. Beat in enough milk to achieve spreading consistency.
Spread frosting between layers, inserting toothpicks to stabilize layers.
Frost top & sides of cakes. Sprinkle with pecans. Store in refrigerator.
Preheat oven to 350°F. Coat a 9"x13" baking dish with cooking spray. Cook potatoes in boiling water until tender, about 15 minutes. Drain, reserving some of the cooking liquid. Peel & quarter the potatoes, then mash with a little of the cooking liquid. Set aside.
In a large skillet, cook the meat over medium-high heat. Drain fat from pan. If using leftover meat, heat & add to the skillet. Stir in mushrooms, vegetables, mushroom & celery soups, salt, & pepper; heat through. Pour into prepared baking dish; cover with mashed potatoes & dot with butter.
Bake in preheated oven for 30 minutes or until potatoes are golden & meat & vegetable mixture is hot & bubbly.