Hazelnut Butter Cup Tart

This tart is a bit like a giant peanut butter cup! I used powdered monk fruit sugar to make it, but in hindsight, I just don’t like that (the cooling sensation puts me off), so I’d recommend using the real stuff, and perhaps using only 1 cup of it instead of 1 ¼ cups. I used bittersweet chocolate instead of milk chocolate, and like it so much that I’m writing that below. I’m wondering whether I could use matzo crackers instead of ice cream cones to make it kosher for Passover… In any event, this was a great tart! The recipe is from Bon Appétit. 

2 ½ cups (350 g) hazelnuts, preferably blanched 

7 oz. quality bittersweet chocolate (about 60 %), chopped (about 1 cup) 

7 oz. quality semisweet chocolate, chopped (about 1 cup) 

2 ¼ tsp. Diamond Crystal or 1 ½ tsp. Morton kosher salt, divided 

4 sugar or waffle ice cream cones 

4 Tbsp. lactose-free butter, at room temperature 

1 Tbsp. vanilla bean paste or vanilla extract (I recommend the paste!) 

1 Tbsp. vegetable oil, plus more for pan 

1 ¼ cups (138 g) powdered sugar (see note above) 

flaky sea salt 

Place a rack in middle of oven and preheat to 350 °F. Toast hazelnuts on a rimmed baking sheet until golden brown in the center, 10–12 minutes. Let cool. If nuts are unblanched, rub together in a clean kitchen towel to remove skins; discard skins. 

Using a paper towel, lightly grease bottom and sides of tart pan with vegetable oil. If you’d like to eventually remove tart from bottom of pan, line with a parchment paper round. Melt bittersweet chocolate, semisweet chocolate, and ¼ tsp. Diamond Crystal or Morton kosher salt in a heatproof bowl set over a saucepan filled with 1" of barely simmering water, stirring with a heatproof rubber spatula, until just melted and smooth, about 5 minutes. Pour about half of chocolate into prepared pan (eyeballing is fine!); set remaining chocolate aside. Using a small spoon, spread chocolate across bottom and up sides of pan, working it all the way to edges of pan. Place on a rimmed baking sheet or large plate and chill in freezer until chocolate is set, at least 10 minutes and up to 30 minutes. 

Crush ice cream cones in a medium bowl until pieces are about peanut-size. (I did this in the food processor, so it makes more sense to put it at this point in the recipe.) Set aside. 

Meanwhile, pulse hazelnuts and remaining 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt in a food processor until a paste forms, about 4 minutes. Add butter, vanilla, and 1 Tbsp. vegetable oil; process until the texture of smooth peanut butter, about 4 minutes. Add powdered sugar; pulse until combined (mixture will be thick). 

Scrape hazelnut butter in the medium-sized bowl containing the crushed ice cream cones. Mix until well combined (using your hands might be most efficient, but I used a rubber spatula). Scrape hazelnut butter filling into chocolate shell and gently press down into shell to compact into an even layer; smooth surface with an offset spatula. 

Scrape remaining melted chocolate over nut butter (reheat slightly if needed), spreading all the way to the edges. Smooth surface with offset spatula or spoon. Sprinkle generously with flaky sea salt, then chill tart in freezer until chocolate is set and sides of tart are pulling away from pan, at least 30 minutes and up to 4 hours. 

Gently pop tart out of pan. (If pan is lined with parchment paper, remove bottom and peel away parchment; discard.) Transfer tart to a large plate and thaw in fridge 30 minutes. 

Let tart sit at room temperature 15–20 minutes before cutting into thin wedges. A knife dipped in hot water and wiped clean will make the neatest slices, but you don’t have to go through the trouble if you don’t want to.