1. Prepare the required materials
2. Purple sweet potato peeled and cut into small pieces, steamed in a pot
3. Put the butter, milk, and sugar into the pot and heat and stir until the sugar melts
4. After letting cool, add egg yolk and low powder and stir evenly
5. Then filter
6. Put the steamed purple sweet potato into the tart crust
7. Pour the tart water, 8-9 minutes full
8. Put it into the preheated oven at 210 degrees, and bake the upper and lower layers for 25 minutes.
9. The aroma is so delicious
