Preheat oven to 350°F
Spray 3 8-inch round baking pans with pam, line bottoms with parchment paper, grease again and set aside.
In small bowl combine cocoa and boiling water with a whisk until smooth. Cool.
In medium bowl stir together flour, baking soda and salt.
In a mixer, beat butter and sugar until fluffy.
Add eggs, one at a time and vanilla.
Slowly add the cocoa mix.
Add ⅓ of the flour mix, then the milk. Then ⅓ of flour and the sour cream. Then, add the past of the flour.
Mix well and divide into the pans.
Bake 28-30 mins until the toothpick comes out clean.
Cool and pop out of pans. Remove parchment.
Freeze until firm.
