- 1 sheet all-butter store-bought puff pastry, thawed
- 3/4 cup sugar plus 1 tablespoon for pastry
- 1 stick unsalted butter, cut into 16 pieces
- 2 teaspoon vanilla extract
- 1/8 teaspoon salt
- 1 1/2 pound sweet potatoes (try to buy potatoes of relatively even width and few bulges), peeled, ends removed, and sliced into 1/8 -inch-thick rounds
- 1 pound large egg
- 1 tablespoon milk
Heat the oven to 375 degrees F.
Line a baking sheet with parchment paper.
Place the puff pastry sheet on your work surface and cut out a 10-inch circle.
Set the circle onto the prepared baking sheet.
Prick the pastry all over with a fork and refrigerate.
Place 3/4 cup of sugar in a small saucepan and cover with 1/4 cup of water.
Gently stir with a spoon to make sure all of the sugar is wet (it should have the consistency of wet sand), place a cover on slightly askew, and bring to a boil over medium-high heat.
Keep the mixture covered until the syrup is clear and producing syrupy-looking medium-size bubbles, 3 to 4 minutes.
Remove the cover and continue to cook until the sugar is a light butterscotch color and its temperature reaches 320 degrees F.
Turn off the heat (the sugar will continue to cook in the pan even though the heat is off).
Once the temperature reaches 350°F (this will take only a few minutes), whisk in the butter, 1/2 tablespoon (1 piece) at a time, waiting until each addition is completely incorporated before adding the next.
Stir in the vanilla and the salt, and pour the caramel into a 10-inch cast iron skillet.
Cover the caramel with the sliced potatoes, starting in the center and overlapping in a spiraling outward circle as you go.
Top with the puff pastry circle.
Beat the egg and the milk together and brush over the pastry, and then sprinkle with the remaining 1 tablespoon of sugar.
Bake until the edges are deep amber and the pastry is puffed and golden, 40 to 45 minutes.
Remove from the oven and cool for 10 minutes before inverting onto a large plate (make sure the diameter of the plate is larger than 10 inches!).
Slice into wedges and serve with or without ice cream.
To make life easier, I use store-bought puff pastry.
Try to source an all-butter kind, like Dufour, which gives the tart a rich flavor and tender texture.