• Preheat oven to 375 degrees F.
• Beat the brown sugar, butter, shortening, milk and vanilla together until light and fluffy. Add the egg and beat just until it is fully blended.
• Whisk together flour, baking soda and salt and add to the bowl. Stir until blended, then stir in the chocolate chips.
• Using a tablespoon or a medium size cookie scoop, scoop dough onto parchment lined or ungreased baking sheets and bake cookies for 10 to 12 minutes. Let cool for about 2 minutes on baking sheet and carefully transfer to a wire rack to cool completely.

Chilled Dough Ball Make Ahead Method

• On a plate lined with plastic wrap, foil or wax paper, drop medium size cookie scoops (or large tablespoons) of dough. Cover and refrigerate until cold, at least 2 hours but ideally a day or two. If storing longer, transfer the dough balls to the freezer.
• Arrange balls of dough on parchment lined baking sheets (or just use one sheet and bake as many balls of dough as you plan to eat).
• Bake on center rack for about 12 minutes or until cookies are brown around the edges.
• Let cool for 3 minutes on the baking sheets, then transfer to wire racks to cool slightly before serving.
• For even better cookies, allow the cookies to cool completely, then store them in a zipper bag or a tin with a slice of bread. The next day they'll be even softer, but still dense and not cakey.