1. Prepare for Baking: Setting the Stage for Success

Preheat Oven: Preheat your oven to 375°F (190°C).

Line Baking Sheets: Line two large baking sheets with parchment paper. This prevents the cookies from sticking and makes cleanup a breeze.

2. Prepare the Lemon Zest and Juice: Maximizing Citrus Flavor

Zest Lemons: Wash and dry all 3 lemons. Using a zester or the fine side of a box grater, zest all 3 lemons, being careful to avoid the bitter white pith.

Juice Lemon: Cut one of the zested lemons in half and juice it. You should have about 2 tablespoons of juice. If not, juice another lemon until you have enough.

Set Aside: Set aside the lemon zest and juice.

3. Prepare the Blueberries (if using fresh): Preventing Sinking

Wash and Dry: If using fresh blueberries, wash and dry them thoroughly.

4. Combine Dry Ingredients: Ensuring Even Distribution

Whisk Together: In a medium bowl, whisk together the flour, cornstarch, baking powder, baking soda, and salt until well combined. Set aside.

5. Melt and Cool Butter: A Key Step for Chewy Texture

Melt Butter: In a small saucepan or microwave-safe bowl, melt the butter completely.

Cool: Let the melted butter cool in the fridge for about 10 minutes. You want it to be liquid but not hot.

6. Cream Together Sugar and Lemon Zest: Infusing with Citrus Aroma

Combine Sugar and Zest: In a large mixing bowl, combine 1 ½ cups of granulated sugar with 1 tablespoon of the reserved lemon zest.

Rub Together: Using your fingers, rub the lemon zest into the sugar until the sugar is fragrant and slightly damp. This releases the essential oils from the zest and infuses the sugar with lemon flavor.

7. Beat in Butter: Creating a Smooth Base

Add Cooled Butter: Pour the cooled melted butter into the bowl with the lemon sugar.

Beat: Using an electric mixer (handheld or stand mixer), beat the mixture on medium speed until well combined and smooth.

8. Incorporate Eggs and Vanilla: Adding Richness and Flavor

Add Eggs: Add the egg and egg yolk to the butter mixture, one at a time, beating well after each addition until fully incorporated.

Add Vanilla: Beat in the vanilla extract until combined.

9. Gradually Add Dry Ingredients: Forming the Dough

Combine: With the mixer on low speed, gradually add the dry ingredients (flour mixture) to the wet ingredients, mixing until just combined.

Tip: Be careful not to overmix the dough. Overmixing can lead to tough cookies.

10. Fold in Blueberries: Adding the Fruity Burst

Gently Fold: Using a rubber spatula, gently fold in the fresh or frozen blueberries until they are evenly distributed throughout the dough.

Tip: If using frozen blueberries, add them to the dough while still frozen to prevent them from bleeding too much color into the dough.

11. Chill the Dough: A Crucial Step for Preventing Spreading

Cover and Freeze: Keep the dough in the bowl, cover the top with plastic wrap, and place it in the freezer for at least 1 hour.

Important Note: The recipe author emphasizes that chilling the dough is essential to prevent the cookies from spreading too much during baking. The dough must be frozen, not just refrigerated.

12. Prepare for Baking: Getting Ready to Roll

Preheat Oven: After the dough has chilled for 1 hour, preheat your oven to 325°F (165°C).

13. Prepare the Lemon Sugar Coating (Optional): An Extra Layer of Flavor

Combine Sugar and Zest: In a small, shallow bowl, whisk together the remaining 3 tablespoons of granulated sugar and the remaining 1 teaspoon of lemon zest.

14. Shape and Coat the Cookies: Ready for the Oven

Scoop Dough: Remove the chilled dough from the freezer. Using a medium cookie scoop (about 2 tablespoons), scoop out portions of dough.

Roll in Sugar (Optional): If desired, roll each dough ball in the prepared lemon sugar mixture until it’s evenly coated.

Place on Baking Sheets: Place the dough balls on the prepared baking sheets, leaving about 3 inches between each cookie. This is more space than usual, but it is necessary because these cookies are frozen when they go in the oven.

15. Bake to Perfection: Achieving a Soft and Chewy Texture

Bake in Batches: Bake the cookies, one sheet at a time, for 15-16 minutes.

Check for Doneness: The cookies are done when the edges are set and just beginning to turn a light golden brown. The centers should still be slightly soft. The recipe author notes that they will be very soft when they come out of the oven.

Tip: Do not overbake, or the cookies will be dry.

Optional: Reshape Cookies: Immediately after removing the cookies from the oven, you can use a large, round cookie cutter to swirl around each cookie, reshaping them into perfect circles if desired.

16. Cool the Cookies: Setting the Texture

Cool on Baking Sheet: Let the cookies cool on the baking sheet for at least 10 minutes. This allows them to firm up and prevents them from breaking when transferred.

Transfer to Wire Rack: Carefully transfer the cookies to a wire rack to cool completely.

17. Make the Glaze (Optional): A Sweet Raspberry Drizzle

Combine Ingredients: While the cookies are cooling, you can make the optional glaze. In a small bowl, whisk together 1 cup of confectioners’ sugar, 1 or 2 mashed frozen raspberries, and 1 tablespoon plus 1 teaspoon of water until smooth.

Adjust Consistency: If the glaze is too thick, add more water, ½ teaspoon at a time, until it reaches a drizzling consistency. If it’s too thin, add more powdered sugar, 1 tablespoon at a time.

18. Drizzle and Serve: The Finishing Touches

Drizzle Glaze: Once the cookies are completely cool, drizzle the raspberry glaze over the tops.

Garnish (Optional): If desired, garnish with extra lemon zest while the glaze is still wet.

Let Glaze Set: Let the glaze set completely before serving.