Cream the Butter and Sugar: In a large mixing bowl, begin by creaming together 1 cup of softened unsalted butter and 1 cup of granulated sugar using a hand mixer or stand mixer. Beat for about 3 minutes until the mixture becomes pale and airy. Next, add in 1 large egg and 2 tablespoons of fresh lemon zest, mixing until well combined, and you have a fluffy base for your Lemon Raspberry Cookies.

Mix the Dry Ingredients: In a separate bowl, whisk together 2.5 cups of all-purpose flour, 2 teaspoons of cornstarch, ½ teaspoon of baking soda, and ½ teaspoon of salt. Gradually incorporate this dry mixture into the wet ingredients using a spatula or mixer on low speed, mixing until a thick dough forms.

Fold in Raspberries and Jam: Gently fold in ½ cup of finely chopped fresh raspberries to your cookie dough, ensuring they are evenly distributed. Then, take 3 tablespoons of seedless raspberry jam and dollop it onto the dough. Carefully swirl the jam into the dough with a spatula, being mindful not to overmix.

Prepare for Baking: Preheat your oven to 350°F (175°C) while you prepare the baking sheet. Line a baking sheet with parchment paper to prevent the cookies from sticking. Using a cookie scoop or tablespoon, drop generous 2-tablespoon mounds of dough onto the lined sheet, leaving about 2 inches between each mound.

Bake the Cookies: Place the baking sheet in the preheated oven and bake for 10-12 minutes, or until the edges are lightly golden and the centers appear slightly underbaked.

Cool and Dust: Once out of the oven, allow the cookies to cool on the baking sheet for about 5 minutes. After cooling, transfer the cookies to a wire rack and sprinkle them lightly with powdered sugar.