Follow the instructions to make the tart crust and stop at Step 8. Bake in an 170℃/338F preheated oven for 15 minutes. Remove your baking beans or weights, cover the edges with aluminium foil, and bake for a further 10 minutes.
Bake until the bottom is lightly browned. If it's not baked enough, the bottom will be too soft and won't be crusty. You could also bake it for approximately 15 minutes without any baking weights.
Rinse the sweet potato for decoration and dice. Soak in water to remove any bitterness. Simmer and reduce in a small amount of sugar and water.
Rinse the other sweet potato and peel. Soak in water to remove any bitterness. Chop it up and boil until soft. Drain in a colander or sieve, then return it into the pot.
Mash while it's hot. Add ☆ ingredients in order. Cook over low heat until the water evaporates and becomes thick. Mix and knead making sure it doesn't burn.
Turn heat off. Add beaten egg yolks in small batches and mix quickly. Add vanilla.
Pour the filling into the half-baked crust from Step 1 and even out the surface. Combine all ★ ingredients and brush on top. Top with sweet potatoes for decoration and brush the ★ mixture as well.
Bake in a 170℃/338F preheated oven for approximately 25 minutes.
Let it cool. Cut using a warm knife.
I noted to boil the sweet potatoes, but you could also wrap them unpeeled with aluminum foil and bake in the oven or steam in a steamer. This improves its sweet flavor and makes it even more delicious.
If you're using an electric oven, make sure to add about 10℃/50F to the temperature.
Peel skin from the sweet potatoes for decoration if you'd wish. To make the tarts taste even more smooth, pass the boiled and mashed potatoes through a sieve.
Story Behind this Recipe
I make these tarts frequently during autumn. It's very simple and delicious!
Bake the tart crust until the bottom is only slightly browned. Bake for 8 minutes after removing weight. Brush on a small amount of beaten eggs (also okay with yolk or white) and bake for another 2 minutes. This prevents any liquid from the filling to soak in, making the tart crusty overall. You could also add cinnamon or salt into the filling, or use brandy instead of vanilla.