Step 1

Position a rack in the middle of the oven and preheat to 350 degrees. Line a rimmed baking sheet (any size, but a quarter- or eighth-sheet is perfect) with parchment paper.

Step 2

In a small bowl, combine the butter, light brown sugar and granulated sugar and stir with a spatula until well combined. Pour in the milk and mix until creamy. Add the flour, baking powder, baking soda and fine salt and mix until a soft but not sticky dough forms. Add the chocolate and stir to combine. If needed, mix in a little extra flour, 1 teaspoon at a time, adding just enough to make the dough lose its stickiness but not become stiff.

Step 3

Shape the dough into a ball and place on the prepared baking sheet. If you prefer a thick and chewy cookie, pop the pan into the freezer to chill for 5 to 10 minutes. Bake for 16 to 20 minutes, or until golden around the edges and a little paler in the center. If you have chilled the dough, you may need the higher end of the time range. Sprinkle with the flaky salt, if using, and let cool on the pan. Serve warm or at room temperature.