Melt the chocolate in a large microwave-safe bowl or in a double boiler over simmering water.
Once the chocolate is melted and smooth, stir in the corn syrup and the butter, stirring until the butter is melted. Stir in the powdered milk and the vanilla extract.
Add a cup of the powdered sugar and stir until it is incorporated. Once that sugar is mixed in, add a second cup of powdered sugar and stir to mix. At this point the dough will start getting stiff and it might be difficult to stir more powdered sugar into the candy.
Dust your work surface with powdered sugar, and knead the candy until it is smooth. If it is still very soft, knead in more powdered sugar until it is firm but not dry or crumbly. You might need up to 3 cups of powdered sugar total.
Once the Tootsie Roll candy is smooth and a perfect firm but supple texture, break off a palm-sized piece and roll it into a long, thin rope. Using a sharp knife, cut it into small pieces and place them on a baking sheet. Repeat until you have formed all of the Tootsie Roll dough into small pieces. Depending on the size of the rolls, you should get 80-100 pieces.
Refrigerate the tray of Tootsie Rolls until they firm up, for about 1 hour. Store Tootsie Rolls in an airtight container in the refrigerator for up to two weeks. You can wrap them individually in waxed paper or cling wrap if they start to stick together because of condensation from the refrigerator. Bring Tootsie Rolls to room temperature before serving.