1. Prepare for Baking: Setting the Stage for Success

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Line Baking Sheets: Line two large baking sheets with parchment paper. This will prevent the cookies from sticking and make cleanup a breeze.

2. Combine Dry Ingredients: Ensuring Even Distribution

1. Whisk Together: In a medium bowl, whisk together the all-purpose flour, cornstarch, and salt.
   • Tip: Whisking helps to aerate the dry ingredients and ensures that the salt and cornstarch are evenly distributed.
2. Set Aside: Set the bowl of dry ingredients aside while you prepare the wet ingredients.

3. Cream Together Butter and Sugars: The Foundation of Flavor and Texture

1. Combine Butter and Sugars: In the large bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a hand mixer, combine the softened butter, brown sugar, and granulated sugar.
2. Cream: Beat the butter and sugars together on medium speed, gradually increasing to medium-high, until the mixture is light and fluffy. This should take about 2-3 minutes. Proper creaming incorporates air into the mixture, resulting in a tender cookie texture.

4. Incorporate Egg Yolk and Extracts: Adding Moisture and Flavor

1. Add Egg Yolk: Add the egg yolk to the creamed butter and sugar mixture. Beat until well combined.
2. Add Extracts: Scrape down the sides of the bowl with a rubber spatula. Add the vanilla extract and almond extract (if using) to the bowl. Mix until evenly incorporated.

5. Gradually Add Dry Ingredients: Bringing the Dough Together

1. 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 develop the gluten in the flour, resulting in a tough cookie.

6. Shape the Cookies: Creating the Heart Indentations

1. Scoop Dough: Use a 1-tablespoon cookie scoop or a spoon to scoop out portions of dough.
2. Roll into Balls: Roll each portion of dough between your palms to form a smooth, round ball.
3. Place on Baking Sheets: Place the dough balls on the prepared baking sheets, leaving about 2 inches between each cookie to allow for spreading.
4. Create Indentations: Gently press the center of each dough ball with your pinky finger to create a heart-shaped indentation.
   • Tip: If you don’t want to use your finger, the handle of a wooden spoon or the back of a small measuring spoon can also be used.

7. Chill the Dough: Ensuring Proper Shape Retention

1. Freeze or Refrigerate: Place the baking sheets with the indented cookie dough balls into the freezer for 30 minutes or the refrigerator for 1 hour.
   • Why Chill: Chilling the dough helps the cookies maintain their shape during baking and prevents excessive spreading.

8. Prepare the Jam: Making it Easier to Fill

1. Warm Jam: While the dough is chilling, place the raspberry jam in a small microwave-safe bowl.
2. Microwave Briefly: Microwave the jam for 10-15 seconds, or until it’s slightly runny and easier to spoon.

9. Fill the Indentations: Adding the Sweet, Fruity Center

1. Remove from Freezer/Refrigerator: Remove the baking sheets with the chilled cookie dough from the freezer or refrigerator.
2. Fill with Jam: Using a ¼ teaspoon or a very small spoon, carefully fill each heart-shaped indentation with about ½ teaspoon of the warmed raspberry jam.

10. Bake to Golden Perfection: Achieving the Ideal Texture

1. Preheat: Ensure your oven is preheated to 375F
2. Bake: Bake the cookies for 10-12 minutes.
   • Check for Doneness: The cookies are done when the edges just start to turn a light golden brown. The centers will still be slightly soft.
3. Cool on Baking Sheets: Remove the baking sheets from the oven and let the cookies cool on the sheets for about 5 minutes. This allows them to firm up slightly and prevents them from breaking when transferred.
4. Transfer to Wire Rack: Carefully transfer the cookies to a wire rack to cool completely.