Make the Hazelnut Praline Powder

See recipe.

Make the Dough

Cut the butter into 1 inch cubes and refrigerate until ready to use.

Into a small bowl, sift together the flour, baking soda, and salt. Whisk to combine well.

Food Processor Method In a food processor, place the superfine sugar. (Granulated sugar can also be used, processed for several minutes or until very fine.) With the motor running, add the butter cubes. Add the praline powder and oil and process until smooth and creamy, about 20 seconds. With the motor running, add the egg and vanilla and process until incorporated. Scrape down the sides of the bowl. Add the flour mixture and pulse just until incorporated.

Stand Mixer Method Soften the butter to 65° to 75°F/19° to 23°C.

In the bowl of a stand mixer fitted with the flat beater, on medium speed, beat together the superfine sugar, butter, praline powder, and oil for several minutes, or until very smooth and creamy. Add the egg and vanilla and beat until incorporated, scraping down the sides of the bowl. On low speed, gradually beat in the flour mixture just until incorporated.

Preheat the Oven

Twenty minutes or longer before baking, set an oven rack in the middle of the oven and preheat the oven to 350°F/175°C.

Chill the Dough

Scrape the dough onto a piece of plastic wrap and divide it in half, about 5.6 ounces/159 grams each. Wrap each piece in plastic wrap and refrigerate for a minimum of 1 hour before shaping.

Preheat the Oven

Thirty minutes or longer before baking, set an oven rack in the middle of the oven and preheat the oven to 375°F/190°C.

Roll the Dough into Balls

Scoop out 15 rounded teaspoons of dough (0.4 ounce/10 grams each). Roll each piece of dough between the palms of your hands into a 1 inch ball. Set the dough balls a minimum of 1½ inches apart on a cookie sheet and press them down to 1½ inches wide by ½ inch high.

Bake the Cookies

Bake for 7 minutes. For even baking, rotate the cookie sheet halfway around. Continue baking for 5 to 7 minutes, or until lightly browned and set. A fingertip pressed lightly onto the top of a cookie will yield slightly to the pressure.

Cool the Cookies

Set the cookie sheet on a wire rack and let the cookies cool for 1 minute so that they will be firm enough to transfer to a wire rack to finish cooling. Use a pancake turner to lift the cookies onto another wire rack.

While the cookies are baking, shape the dough for the next batch.