Combine dry ingredients, flour, baking powder, baking soda, spice mix and salt in a bowl. Whisk together.
Step 2
Cream oil and sugar in a mixer. Add the egg, egg yolk and vanilla and beat to combine.
Step 3
Add the flour mix to the wet ingredients alternately with sour milk and continue to beat until combined.
Step 4
Pour spice cake batter into greased cake pans and bake until a toothpick inserted in the center of the cake comes out clean.
Step 5
Cool for a bit in the pan then move to a wire rack to cool completely.
Step 6
Prepare frosting, by beating butter and cream cheese together on medium-high speed until creamy. Lower speed to medium and add powdered sugar.
Step 7
Add the salt, cream and vanilla and beat until fluffy.
Step 8
To frost the cake, place the first layer on a plate top side down, spread with 1 cup of frosting, place the second layer top side down and frost top of the cake with remaining frosting.