If using fresh ube, Okinawan purple sweet potatoes, or Stokes purple sweet potatoes, peel the skin and then cut into large chunks and steam for about 15 minutes or until easily mash with fork. You can also microwave on high for 8-10 minutes or until soft.
If using frozen grated ube, thaw and then steam for about 10-15 minutes or until easily mashable
Get about 200 grams of purple sweet potatoes or ube to make cookies, you can eat the rest :)
Prepare cookie dough:
Place the dry ingredients in a mixing bowl and whisk to mix. Place mashed potatoes or ube and butter in a stand mixer bowl and fix the paddle attachment to the mixer to cream them until smooth and creamy. Add sugar, vanilla extract, and mix until combined. I need to scrap the side of the mixing bowl halfway to make sure it gets everything. Add in eggs and continue to mix for another 2 minutes on speed
Turn the speed to low and gradually add in the flour mixture and let it mix until combine. Add food coloring or ube extract (if using) and continue to mix until the color is even and you are happy with the purple color.
Chill the dough:
If you use ube or Okinawan sweet potatoes, the dough is very sticky at this point. Stokes purple sweet potatoes don't have as much moisture and the dough is actually not as sticky. I could actually skip chilling the dough with it. Otherwise, cover with plastic wrap and refrigerate for about 1 hour. I let it refrigerate overnight. Don't be alarm if the dough changes color to darker green or brownish on the outside after refrigeration, the inside is still purple
Let the cookie dough out on the counter for about 15 minutes to let it soften a bit. Mix the dough a bit and the Preheat the oven to 325 F. Line the cookie sheet with parchment paper
Shape the cookies:
Scoop about 1 Tbsp of the cookie dough out. Roll it into a ball and place them on lined cookie sheet. If you feel that the dough is getting too sticky and wet by the time you are done shaping them, pop the whole tray in the freezer for 15 minutes. This will prevent the cookies from spreading out too much when you bake them. Only get the tray out when you are ready to bake them. Then generously roll them in confectioners' sugar. Roll them several times to make sure each ball is well-coated
Pop them into the oven. I bake them one tray at a time because my oven is just weird. You'll know your oven better. Let it bake for 14 minutes (my oven took about 16 minutes). They appear to be still very soft when you pull them out from the oven, but they will toughen up a bit as they cool down. The inside is still so soft and gooey
*If you use frozen purple sweet potato or frozen grated ube, make sure you steam them and mash. The water content will affect the consistency of the dough. *If you use ube jam, you may need to adjust the amount of sugar as usually ube halaya (ube jam) is usually sweetened.
Amazingly Soft Ube or Purple Sweet Potato Crinkle Cookies https://whattocooktoday.com/purple-sweet-potato-crinkle-cookies.html