Brazilian Chocolate Truffles

INGREDIENTS
1 can sweetened condensed milk
1 tbsp. unsalted butter
3 tbsp. Unsweetened cocoa powder
½ c. chocolate sprinkles and/or rainbow jimmies
DIRECTIONS
Coat a large shallow pan or platter with butter or cooking spray. In a large saucepan, bring condensed milk, cocoa powder, and butter to a boil, stirring constantly with a rubber spatula. Reduce heat to medium-low and cook for 15 to 20 minutes, stirring constantly until mixture thickens. It should have the consistency of thick frosting.
Pour mixture into prepared pan; let cool completely and become firm (you can refrigerate it to speed up the process).
Grease your hands with butter and shape pieces into 1- to 1 1/2-inch balls. Roll each ball in sprinkles. Place on waxed paper and refrigerate for at least 1 hour before serving.