1. Prepare the cookie dough

1. In a large mixing bowl, cream together the softened butter, granulated sugar, and powdered sugar with an electric mixer until light and fluffy (about 2–3 minutes).
2. Add the egg yolk and vanilla extract, and mix until fully incorporated.
3. Gradually add the flour and salt, mixing just until the dough comes together.
4. Cover the dough with plastic wrap and chill in the refrigerator for 30 minutes.

2. Make the crumble topping

1. In a medium bowl, combine the flour, granulated sugar, brown sugar, and cinnamon (if using).
2. Add the cold butter cubes and use your fingers or a pastry cutter to mix until the mixture resembles coarse crumbs. Refrigerate until ready to use.

3. Assemble the cookies

1. Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
2. Roll the chilled dough into 1.5-inch (3.8 cm) balls and place them on the prepared baking sheets, spacing them about 2 inches (5 cm) apart.
3. Use your thumb or the back of a teaspoon to press a shallow well into the center of each cookie.
4. Spoon about 1/2 teaspoon of raspberry preserves into the center of each well.
5. Sprinkle a generous amount of the crumble topping over the raspberry preserves, pressing gently to adhere.

4. Bake

1. Bake the cookies in the preheated oven for 12–15 minutes, or until the edges are lightly golden and the crumble topping is set.
2. Allow the cookies to cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely.