Start by preheating your oven to 350°F (175°C). Prepare a baking sheet by lining it with parchment paper to prevent the cookies from sticking.
In a large mixing bowl, combine the softened unsalted butter and granulated sugar. Use an electric mixer on medium speed to cream them together until the mixture is light and fluffy, about 3 to 5 minutes.
Add in the egg yolk and almond extract, continuing to beat until they are thoroughly incorporated into the butter-sugar mixture.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt until fully combined. Gradually sift this dry mixture into the wet ingredients, mixing gently until just combined to avoid overworking the dough.
With your hands, scoop and roll the dough into small balls, each about 1 inch in diameter. Place them on your prepared baking sheet, making sure to space them approximately 2 inches apart to allow for spreading.
Take your thumb or the back of a measuring spoon and create an indentation in the center of each dough ball, pressing down gently but firmly.
Carefully fill the indentation of each cookie with about 1/2 teaspoon of raspberry preserves, making sure not to overfill.
Sprinkle a few sliced almonds around the preserves in each cookie, gently pressing them into the dough to ensure they stick during baking.
Bake the cookies in your preheated oven for 12 to 15 minutes, or until the edges are a lovely light golden brown. Keep an eye on them to prevent overbaking.
Once baked, remove the cookies from the oven and allow them to cool on the baking sheet for about 5 minutes. Then, transfer them to a wire rack to cool completely.
Once the cookies are fully cooled, you can choose to dust them lightly with powdered sugar for that extra touch of sweetness and an elegant finish.
Notes
Arrange the cookies on a decorative plate, perhaps with fresh raspberries or whole almonds as a garnish to enhance their appeal.