Ingredients:
Dough
2 3/4 cups(330 grams) all-purpose flour
1 tablespoonpacked (13 grams) dark brown sugar
2 teaspoonskosher salt
1 cup(2 sticks) unsalted butter, cold and cubed
1/2 cup(113 grams) cold water
Filling
1/2 cuppacked (106 grams) dark brown sugar
1/2 cup(156 grams) light corn syrup
6 tablespoons(3/4 stick) unsalted butter, melted
2 large eggs, beaten
1 1/2 teaspoonsvanilla extract
1/2 teaspoonkosher salt
Directions:
Make the dough: Add the flour, sugar, and salt, to a large bowl and stir to combine. Add the butter to the flour mixture and use your hands to break up the butter until the butter is the size of peas. Drizzle the water, 1 tablespoon at a time, over the flour mixture, using your hands to mix the dough.
Turn the dough onto a clean work surface and use your hands to shape until it comes together in a 6-inch disk. The dough will seem crumbly at first, but will come together in under 1 minute. Wrap in plastic wrap and transfer to the refrigerator to chill for at least 30 minutes, or up to 2 days.
Heat the oven to 400°F. Make the filling: In a large liquid measuring cup, add the dark brown sugar, corn syrup, butter, eggs, vanilla, and salt and whisk until smooth.
On a lightly floured work surface, roll the dough out to ¼ inch. Use a 4½-inch round cookie or biscuit cutter (or a cup or bowl in a pinch) to cut out 12 circles. If you run out of dough, simply reroll the scraps until you have enough cutouts.
Place each dough circle in a muffin tin and press down. As the dough fills the tin, the edges will naturally ruffle. To get a classic butter tart shape, tug and pinch 4 or 5 corners of the dough into the center to form a clover shape.
Place the muffin tin on a rimmed sheet pan to catch any drips. Fill each dough in the muffin tin three-quarters of the way up (about 2 tablespoons per tart) with the filling mixture, making sure not to fill over the edge of the dough.
Bake until the top of the crust is lightly golden brown and the filling is bubbly and deep golden brown, 20 to 25 minutes.
Let the tarts cool to room temperature before removing from the muffin tin. Store in a sealed container at room temperature for up to 1 week, although I’ve never had them last for more than 24 hours.