Step 1

Mix butter, milk, salt, brown and white sugars in a heavy pan on medium heat. Bring to a boil and stir continuously for 6 minutes.

Step 2

Remove from heat and cool briefly, then add vanilla, cocoa powder, and confectioner's sugar. Beat with an electric mixer until fudge is smooth and thick.

Step 3

Pour onto a buttered baking pan. When cool enough to touch, use a spatula to help roll mixture into log form, wrap it in plastic wrap and place in freezer for 20 minutes.

Step 4

Slice to serve. Enjoy!