Whisk together the pumpkin, sugar, oil, and eggs until well blended.
Mix in the spices and salt. Fold in the flour and baking soda until everything is well incorporated, but don't over beat.
Spread the batter into your prepared pan. Bake for 25- 30 minutes or until done in the center and a toothpick comes out without wet batter clinging to it.
To make the frosting, heat the half and half, butter, and brown sugar in a saucepan until it comes to a boil, stirring constantly. Take off the heat and beat in the vanilla and sifted confectioner's sugar. Quickly spread over the cake, the frosting will set up quickly.
While the frosting is still soft top with toasted pecans.