1Heat oven to 350. Grease and flour a large cookie baking pan 17" 1/2 x 12."
2Combine cake mix, eggs, pumpkin pie spice and water in a large mixing bowl. Mix on medium speed about 2 minutes. On slowest speed add pumpkin and mix just until combined. Pour into prepared pan and bake about 15 minutes, or until firm in the center and tests done. Allow to cool about 10 minutes and then spread HOT carmel frosting over cake.
Melt the butter in medium size sauce pan, stir in brown sugar and mix until dissolved. Bring to a boil and cook stirring constantly for 2 minutes. Add milk and vanilla, returning to boil. Remove from heat and stir in powdered sugar. Immediately pour over cake and spread quickly, this gets firm fast.