Hot Fudge Sauce

1/3 cup baking cocoa
1 cup sugar
1/4 cup milk
1/2 cup butter
Pinch of salt

Mix all ingredients and boil on medium-high heat for 1 minute, until sauce is a little thicker, but not a lot. (You can test it by drizzling a small amount on ice cream. If it's too chewy, put the sauce back on the stove and add a little more milk.)