4 tablespoons butter or margarine
1 1/2 cups milk
3 cups granulated sugar
2/3 cup cocoa
1/4 teaspoon cream of tartar
1 teaspoon vanilla extract

Melt butter or margarine in a large (10-inch) skillet or heavy pan; add milk and heat to boiling. Combine sugar, cocoa and cream of tartar; stir well into heated milk, using a wooden spoon. Continue stirring until mixture boils. Lower heat and cook gently (don't let it boil too hard as it may run over or stick to the bottom), without stirring, to a soft-ball stage (236 degrees F), about 15 minutes.

Remove from heat. Let stand, without moving or stirring, until candy is barely lukewarm 110 degrees F). Add vanilla extract. Stir-beat with a heavy spoon until candy becomes creamy and loses its gloss, about 8 minutes. Pour into lightly greased 8-inch square pan. Cut into pieces while still warm.

Makes about 1 1/2 pounds candy.

Kneaded Cocoa Fudge
When candy starts to firm, pour from pan onto a hard surface and knead with hands until it is very creamy. Shape into rolls or 1-inch balls, or pat into a greased pan.