Pour the milk into a small saucepan and whisk in the powdered milk and honey. Place over medium heat and bring to 120°F on an instant-read thermometer. Once the milk has reached has reached the target temperature, pour it into a cylindrical plastic container, reserving 1/2 cup. Whisk the reserved milk into the yogurt and add it back to the milk mixture.
Place the container into a narrow wine bucket lined with a heating pad. Set the heating pad to medium. Let the mixture ferment for 3 to 12 hours, making sure the temperature stays as close to 115°F as possible.
After the fermentation is complete, refrigerate overnight.