Step 1: Prepare the Chocolate Cookie Dough

1. Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
3. Beat in the egg and vanilla extract until fully incorporated.
4. In a separate bowl, whisk together the all-purpose flour, cornstarch, black cocoa powder, crushed Oreos, baking soda, and salt.
5. Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
6. Fold in the semi-sweet chocolate chips.

Step 2: Bake the Cookies

1. Scoop 2-tablespoon portions of dough and roll into balls. Place them on the prepared baking sheet, spacing them about 2 inches apart.
2. Slightly flatten the dough balls with your palm or the back of a spoon.
3. Bake for 10-12 minutes, or until the cookies are set but still soft in the center.
4. Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.

Step 3: Make the Frosting

1. In a medium bowl, beat together the cream cheese and butter until smooth and creamy.
2. Add the powdered sugar, vanilla extract, and strawberry flavoring (if using). Mix until smooth.
3. Gently fold in half of the strawberry jam, leaving streaks for texture.

Step 4: Assemble the Cookies

1. Once the cookies have completely cooled, pipe or spread a generous layer of the cheesecake frosting onto each cookie.
2. Top each cookie with a small dollop of the remaining strawberry jam for a burst of fruity flavor.