Adjust oven racks to upper and lower middle positions and preheat the oven to 350 degrees. Place hazelnuts on a rimmed baking sheet. Toast in the oven until golden and fragrant, about 10 minutes. Transfer nuts to a clean kitchen towel and wrap them inside allowing the nuts to steam for a minute or so. Vigorously rub the nuts between the kitchen towel to remove the skins (don’t worry if all the skins don’t come off).

Transfer the toasted hazelnuts to a food processor along with flour and salt. Process until the mixture is finely ground.

Place butter and sugar in the work bowl of a stand mixer. Mix on medium until light and fluffy, about 3 minutes. Add egg yolk and extracts and mix until fully combined. Slowly add flour and hazelnut mixture and mix on low until just combined.

Roll the dough into tablespoon-sized balls using the palms of your hands. Place each dough ball inside a mini baking cup. Divide the filled mini baking cups between two rimmed baking sheets. Press the back of a rounded teaspoon in the center of each cookie.

Bake cookies for 16-18 minutes or until just golden brown on the edges, rotating the baking sheets halfway through. Immediately after the cookies come out of the oven, reinforce the well in the center of each cookie with a clean rounded teaspoon. Cool cookies on the baking sheets for 5 minutes and then transfer to a wire rack to cool completely.

Meanwhile, make the raspberry filling. Heat the jam in a saucepan over medium low heat until bubbling. Pour through a fine mesh strainer, stirring and pressing on the seeds to extract as much of the jam as possible. Discard the seeds. Carefully spoon the warm jam into the center of the cooled cookies. Allow jam to set slightly before serving. Sprinkle with powdered sugar if desired.