Step 1: Preheat the Oven and Prepare the Baking Sheet

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent the cookies from sticking and to make cleanup easier.

Step 2: Mix the Dry Ingredients

In a medium bowl, whisk together 1 1/2 cups all-purpose flour, 1/2 teaspoon baking powder, and 1/4 teaspoon salt. Set the mixture aside.

Step 3: Cream the Butter and Sugar

In a large bowl, cream together 1/2 cup unsalted butter and 1/2 cup granulated sugar. Use an electric mixer on medium speed for about 2-3 minutes until the mixture is light and fluffy.

Step 4: Add Egg and Vanilla

Add 1 large egg and 1 teaspoon vanilla extract to the butter mixture. Beat until fully combined.

Step 5: Combine Wet and Dry Ingredients

Gradually mix the dry ingredients into the wet ingredients. Stir until a dough forms. You may need to use your hands to bring the dough together.

Step 6: Chill the Dough

Chill the dough in the refrigerator for 15 minutes. This step makes the dough easier to roll out and shape.

Step 7: Roll Out the Dough

On a lightly floured surface, roll out the dough into a rectangular shape, about 1/4 inch thick.

Step 8: Add the Blueberry Jam

Spread 1/2 cup of blueberry jam evenly across the dough, leaving a small border around the edges.

Step 9: Roll and Slice the Dough

Carefully roll the dough into a log starting from the long side. Slice the dough into 1/2-inch thick rounds and place them on the prepared baking sheet.

Step 10: Bake

Bake the cookies for 12-15 minutes or until the edges are lightly golden. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.