1. **Prepare the Cookie Dough:**

2. 1. In a medium bowl, whisk together flour, baking soda, and salt. Set aside.

3. 2. In a large bowl with an electric mixer, cream together softened butter, granulated sugar, and brown sugar until light and fluffy (about 2-3 minutes).

4. 3. Beat in eggs one at a time, then stir in vanilla extract until well combined.

5. 4. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Do not overmix.

6. 5. Fold in the chocolate chips until evenly distributed.

7.

8. **Chill the Dough:**

9. 6. Divide the dough in half. Wrap each half in plastic wrap and chill in the refrigerator for at least 30 minutes, or up to 2 hours. This helps prevent spreading.

10.

11. **Bake the Cookie Layers:**

12. 7. Preheat oven to 350°F (175°C). Grease and flour two 8-inch round cake pans, or line with parchment paper circles.

13. 8. Press one half of the chilled dough evenly into each prepared cake pan. For perfectly flat tops, use a second piece of parchment paper and the bottom of a pan to gently press down the dough.

14. 9. Bake for 25-30 minutes, or until the edges are golden brown and the center is set but still looks slightly soft (it will continue to bake as it cools). Avoid overbaking for a chewy texture.

15.

16. **Cool the Cookies:**

17. 10. Let the cookie layers cool in the pans for 10-15 minutes before carefully inverting them onto a wire rack to cool completely. They must be entirely cool before frosting, about 1-2 hours.

18.

19. **Make the Vanilla Buttercream:**

20. 11. In a large bowl with an electric mixer, beat the softened butter on medium speed until creamy (about 2 minutes).

21. 12. Gradually add the sifted powdered sugar, ½ cup at a time, mixing on low until incorporated, then increasing speed to medium. Continue until all sugar is added.

22. 13. Pour in the heavy cream/milk and vanilla extract, and add a pinch of salt. Beat on medium-high speed for another 3-5 minutes, until light, fluffy, and smooth. If too thick, add more cream 1 teaspoon at a time; if too thin, add more powdered sugar.

23.

24. **Assemble the Cake:**

25. 14. Place one cooled cookie layer on your serving plate or cake stand.

26. 15. Spread about ⅓ to ½ of the buttercream frosting evenly over the top of the first cookie layer.

27. 16. Carefully place the second cookie layer on top of the frosting.

28. 17. Use the remaining frosting to frost the top and sides of the cake. Use an offset spatula or knife to create smooth sides or decorative swirls.

29. 18. Garnish with extra chocolate chips or sprinkles, if desired.

30. 19. Serve immediately or chill until ready to serve. Let come to room temperature for optimal flavor and texture before serving.