Heat milk in a small saucepan over medium heat until it begins to bubble. Stir powdered milk and sugar into the hot milk until dissolved. Remove from heat and let cool until an instant-read thermometer reads 110 degrees F (43 degrees C).

Place yogurt in a bowl and add a small amount of warmed milk mixture; combine thoroughly. Pour yogurt mixture back into the saucepan with warmed milk in a thin stream, stirring constantly, until thoroughly blended. Add heavy cream and maple flavoring. Stir well to combine.

Pour milk-cream mixture into 7 individual serving jars. Process in a yogurt maker, according to manufacturer's instructions, for 8 hours. Chill at least 3 hours before serving.