Cake: Whisk together oil, pumpkin, and sugar. Beat in eggs. Add dry ingredients and mix well.
Pour into a well greased and floured Bundt cake pan.
Bake at 350° for 50-60 minutes or till toothpick comes out clean. Cool in pan 10 minutes, then invert on cooling rack. Cool completely and frost.
Frosting: Beat cream cheese and butter till smooth. Beat in powdered sugar, cinnamon, and vanilla. If you need to add a little milk to achieve the right consistency, go right ahead.
Notes
-I often use light cream cheese, which is softer; then I don't need milk.