Why will you love this tart? Its tender rye crust features delicate texture and mild rye flavor. Its bottom layer of crunchy toasted nuts is aromatic and flavorful; and its salted caramel filling is wonderfully gooey and sticky — that’s why!
To make the pastry: Combine the flours, sugar, and salt in a medium bowl.
Add the butter and toss with the dry ingredients, pressing the butter cubes between your thumbs and forefingers to create flattened, flour-coated pieces roughly 1/4” to 1/2” in size. Work as quickly as possible so as not to warm up the butter too much. You can also use a pastry blender or your stand mixer to work the butter into the dry ingredients.
Add 1 tablespoon of ice water at a time, tossing it thoroughly with the flour-butter mixture; a bowl scraper is a handy tool here. Continue to add water until the dough is barely cohesive, with some dry bits remaining.
Transfer the crumbly dough to a clean work surface or a piece of parchment and press it into a disk. Wrap the dough securely and chill it for at least 1 hour, preferably 2 to 3 hours. While you’re waiting, prepare the nuts and caramel.
To prepare the nuts: Preheat the oven to 350°F.
Place the nuts on a baking sheet and transfer them to the oven to toast until they’ve taken on just a little bit of color, about 10 to 12 minutes.
Remove the nuts from the oven and set them aside to cool.
To make the caramel: In a deep, heavy-bottomed saucepan with a capacity of at least 1 1/2 quarts (the syrup will bubble up during cooking), combine the sugar, water, and salt. Stir briefly to combine, then place over medium-high heat.
When the mixture comes to a boil, reduce the heat to medium and cook without stirring. Watch carefully; as the syrup begins to turn golden at the edges, swirl the pan gently without lifting it off the heat to even out the color.
Continue to cook the syrup, swirling the pan regularly and brushing the sides of the pan with water if any sugar crystals form, until it darkens to a light amber color and you start to smell a rich caramel aroma.
Remove the pan from the heat and slowly pour in the cream while you stir with a heatproof spatula. Be careful; the sauce will bubble and steam vigorously.
Once the cream has been thoroughly incorporated, return the pan to the heat. When the caramel starts to bubble again, remove the pan from the heat.
Stir in the butter, a tablespoon at a time, until it’s completely melted and the sauce is smooth. Set the caramel aside to cool to room temperature while you prebake your crust.
To bake the crust and assemble the tart: On a lightly floured surface, roll the chilled pastry into a 11” to 12” circle about 1/8” thick. Lay it gently into a 9” round tart pan, pressing it into the corners. Fold the overhanging dough over on itself to reinforce the edge of the tart.
Prick the bottom of the crust with a fork and place it in the freezer for 15 to 20 minutes while you preheat the oven to 400°F.
Remove the crust from the freezer and line it with foil or parchment paper, and fill it with pie weights or dried beans or rice. Bake the crust for 20 minutes. Remove it from the oven, and gently remove the liner and weights, then return it to the oven for 7 to 10 minutes, until the bottom looks dry and the edges are just beginning to turn golden.
Scoop the nuts into the hot crust, then pour in the caramel.
Return the assembled tart to the oven and bake for 10 to 15 minutes, until the caramel is bubbling and the outer crust is golden brown; the cooler your caramel had become, the longer you’ll need to bake the tart.
Remove the tart from the oven and transfer it to a rack to cool completely.
Store any leftover tart at room temperature for up to five days.
