Preheat your oven to 350°F (175°C). Grease a standard loaf pan and line it with parchment paper for easy removal.

In a medium mixing bowl, whisk together the flour, baking soda, and salt to combine.

In a large bowl, cream the softened butter, brown sugar, and 1/4 cup granulated sugar together until light and fluffy (about 2 to 3 minutes with a hand mixer).

Beat in the whole egg and 2 teaspoons vanilla extract until smooth.

Gradually add the dry flour mixture to the butter mixture, mixing until just combined. Fold in the chocolate chips with a spatula.

To prepare the cheesecake filling, beat the softened cream cheese with 1/4 cup sugar, egg yolk, and 1/2 teaspoon vanilla extract until smooth and creamy.

Scoop out tablespoon-sized portions of the cookie dough, roll them gently into balls, and flatten slightly with your hands.

In your prepared loaf pan, layer some flattened cookie dough balls, then drop small spoonfuls of cheesecake filling between them. Continue alternating layers of cookie dough and cheesecake until all the dough and filling are used up.

Bake for 40 to 45 minutes, or until the loaf turns golden brown on top and is set in the center. If it seems to be browning too quickly, loosely tent with foil for the last 10 minutes.

Allow the loaf to cool in the pan for about 15 minutes, then carefully lift it out and transfer to a wire rack to cool fully.

Once cool, drizzle the loaf with melted chocolate or chocolate glaze if desired. Slice and serve!