Preheat the oven. Preheat the oven to 350°F with two racks positioned in the upper-middle and lower-middle positions. Then, line 2 baking sheets with parchment paper.
Cream the butter and sugar. Cream the butter and light brown sugar at medium speed in a stand mixer until light and fluffy, for about 5 minutes. Then, beat in the egg and vanilla extract until fully incorporated, scraping down the sides of the bowl as needed.
Combine the dry and wet ingredients. Whisk together the flour, baking soda, and salt in a large bowl. On low speed, add the dry ingredients to the butter mixture, ½ cup at a time, alternating with the milk. Begin and end with the flour mixture. Next, stir the chocolate chips by hand or at the lowest mixer speed.
Portion the batter. Portion the batter onto the prepared baking sheets using a large cookie scoop or 3 tablespoons. Measure out the first portion, then eyeball the rest. Space them about 2 inches apart. You should have 16 cakes.
Bake the cakes. Bake for 15-18 minutes, rotating the baking sheets halfway through. The cakes are made when a cake tester or toothpick comes out clean, but the cakes should still be soft.
Cool the cakes. Transfer to a cooling rack and allow them to cool completely.