Preheat your oven to 350°F (177°C) and get a 9-inch springform pan ready. 

Lightly grease it with some nonstick spray, then set it aside so everything’s ready when your dough is.

Whisk the flour, baking soda, and salt in a medium bowl until thoroughly blended. Set it aside for now, and let’s work on the buttery goodness.

In a roomy bowl, blend the softened butter and sugars using a mixer until the mixture becomes smooth and light, this usually takes about a minute or so.

Crack in the egg, add the egg yolk, and pour in the vanilla extract into the bowl. Mix everything together until the dough is smooth and velvety. Be sure to sweep the sides of the bowl so no goodness goes to waste.

Slowly fold the dry components into the wet base until everything is evenly incorporated. You can use a mixer on low or just a spatula to gently mix until combined. Don’t overmix, keep it soft and tender!

Now, fold in the semi-sweet chocolate chips. You’ll have a deliciously chocolate-packed dough that’s practically begging to be eaten raw (but let’s save that for later!).

Carefully transfer the dough into the pan and flatten it to create a consistent, smooth layer. Don’t stress if it’s not perfectly smooth, it’ll bake up just fine.

Pop the pan into the preheated oven and bake for 20 to 25 minutes. You’re aiming for golden edges and a top that’s just set and lightly browned. If it’s getting too brown on top, cover it loosely with foil for the last few minutes.

Let the cookie cake rest in the pan until it’s completely cool, ensuring the perfect set. The wait will be tough, but your kitchen will smell amazing!

For the frosting, beat the softened butter in a clean bowl until it’s smooth and fluffy, about a minute. 

Gradually add powdered sugar and cocoa powder. Take your time to avoid a sugar explosion and mix until smooth.

Incorporate the heavy cream, starting with 1 tablespoon, and stir in the vanilla extract. Beat everything together until the frosting is light, fluffy, and easy to pipe.

Allow the cookie cake to cool completely, then gently ease it out of the pan.

Grab a piping bag (or a zip-top bag with a cut corner) and pipe frosting swirls or designs around the edges. It’s time to make it pretty!