Preheat oven to 350℉ (180℃)
Prepare 2 baking sheets by lining with parchment paper or a silicone baking mat.
In a medium bowl, whisk together flour, baking soda, salt and lemon zest.
Using a stand-mixer with the paddle attachment, begin creaming the butter and granulated sugar until light and fluffy (approximately 2 - 4 minutes on medium speed). Scrape the bowl as needed. Note: a hand-mixer may also be used.
Add the egg and lemon juice. Mix on low speed until incorporated.
Add the flour mixture and mix on low speed until combined.
Scoop approximately 1 ½ tablespoons of cookie dough and roll into a ball.
Lightly press each ball of cookie dough in the sprinkles. Place on the prepared baking sheets. Leave approximately 2 inches of space between each cookie.
Use the back of a ½ teaspoon to make an indentation in the center of each cookie.
Bake cookies for 10 - 12 minutes.
While the cookies are still warm, use the back of the ½ teaspoon spoon to increase the indentation in the center of each cookie.
Let cookies cool on the baking sheets for 5 to 10 minutes, then transfer cookies to a wire rack to cool completely.
Fill the center of each cookie with raspberry jam. Enjoy!