Egg custard tarts, or don tot as I grew up calling them, are my sister's favorite. She literally screams when the egg custard tart cart comes rolling by at dim sum; it's kind of embarrassing, but also hilarious. I love them too, especially when I can manage to save room after all of the steamed buns. What's so lovely about these is that even though they're a dessert, they're not overly sweet, which allows room for the eggy flavor to really shine. They're smooth, silky and really comforting.
For the tart crust: Combine the flour and salt in a medium mixing bowl and whisk together. Add the butter and coconut oil and rub between your fingers until nickel-size flakes of fat are evenly dispersed into the flour. Add the cold water and gently mix into a shaggy mass. Turn out onto a piece of plastic wrap, press together into a disc, wrap tightly and refrigerate for at least 1 hour.
Spray a muffin tin with 2 1/2-inch-diameter cavities with cooking spray. On a lightly floured countertop, roll out the dough to 1/8 inch thick. Cut rounds with a 3 1/2-inch cutter or bowl. Press the rounds into the greased muffin tin and refrigerate until firm, 30 minutes to 1 hour.
For the filling: Preheat the oven to 400 degrees F.
While the crust is chilling, bring the sugar, salt and 1/3 cup water to a boil in a small saucepan. Let cool to warmish. In a measuring cup (or something with a spout), beat together the whole eggs and yolk. Add the warm sugar syrup and whisk to combine. Add the cream and almond extract and whisk to combine. Strain the filling through a mesh sieve.
Pour the filling into the prepared shells (they should be about 85% filled). Bake until the filling has puffed up and set and the crust is golden, 30 to 35 minutes. Let cool slightly before removing from the muffin tin and eating. The egg puff will fall, but it’s ok. These will keep in the refrigerator for a couple of days.