In a large bowl, use an electric hand mixer or stand mixer to beat the room temperature butter, brown sugar, and granulated sugar together on medium speed for 2 minutes until smooth and combined.
Mix in the egg and egg yolk until well combined.
Add the flour, baking soda, and salt. Fold the mixture with a rubber spatula just until a soft cookie dough forms. Do not overmix.
Drop dollops of your cooled blueberry jam across the top of the cookie dough. Take a butter knife and gently drag it through the dough in a zig-zag motion to create beautiful blueberry ribbons.
Do not over-mix, or the entire dough will turn completely purple!
Scoop out a large portion of dough (about 3 tablespoons). Flatten it slightly in your hands, place a frozen cheesecake ball directly into the center, and wrap the dough tightly around it.
Roll into a smooth ball, ensuring the cheesecake filling is entirely sealed inside.
Space the cookie balls 3 inches apart on your baking sheets. Bake for 12-14 minutes until the edges are lightly golden, but the centers still look soft.
Let the cookies rest on the hot baking sheet for 10 minutes before moving them to a wire rack to cool completely.