Prepping the tart: I recommend using the dough of "Easy Crunchy Cinnamon Cookies" that's only takes 5 minutes before baking. Double the ingredients when using a 21 cm tart pan. If using a 18 cm pan, make the recipe as is.
Roll out the dough to 4 mm thickness and press into the tart pan. Poke a few holes on the bottom with a fork.
Make cookies with leftover dough, or press into madeleine pans to make mini tarts.
Bake for 20 minutes in a 180℃ preheated oven.
Prepping the sweet potatoes: Chop the sweet potatoes into decent sizes and put into a pan. Add enough water to soak the sweet potatoes and heat. Test with a skewer and make sure you can poke a hole thoroughly.
Transfer the heated sweet potatoes into a bowl. Mash with a masher or a wooden pestle.
Measure the ☆ ingredients as you add to the bowl. Mash and mix. (adjust the amount of sugar depending on the sweetness of the sweet potatoes.)
It will turn out like this.
Fill the tart crust.
Cover with plastic wrap and press down to shape.
Mix the egg yolk (for shine) in cutting motion. Brush on the surface.
Bake for 15 to 20 minutes in a 180-200℃ preheated oven.
Done. The tart crusts are really crunchy when freshly baked. From the following day onwards, it will become more moist.
Story Behind this Recipe
I decided to make tarts with sweet potatoes so that it's easy to carry when giving it away as a gift.
Adding cinnamon to the tart crust is optional, omit it if you wish I think there will be leftovers of the sweet potato mixture when using a 18 cm tart pan, so roll it up into balls of preferred sizes to bake with the tart. If you wish to press the mixture through a sieve, do so after mixing in the ingredients.