In a medium bowl, whisk together the 2¼ cups all-purpose flour, 2 tablespoons malted milk powder, 1 tablespoon corn starch, and ½ teaspoon baking soda.
In the bowl of a stand mixer fitted with a paddle attachment, cream together 1 cup light brown sugar, ¾ cup salted butter (melted), ½ cup granulated sugar, 1 tablespoon vanilla bean paste, and 1 teaspoon salt until smooth. 1 min on 2 and 1 min on 4 speed.
Add in 1 large egg and 1 additional large egg yolk and beat until light and creamy. About 5 minutes.
Add the dry ingredients to the wet ingredients a little at a time, mixing between each addition.
Fold in most of the 2 cups chocolate chips.
Measure the dough into 1/4 cup-sized balls, or about 3 ounces each. I use a #16 cookie scoop. If desired, press additional chocolate chips into the top of the dough.
Chill uncovered in the fridge for 2 hours.
Preheat oven to 325°F and place balls on a parchment-lined cookie sheet at least 3 inches apart. Bake for 15 to 17 minutes until the edges are golden brown.
Sprinkle the cookies with flaky sea salt (if using) as soon as they come out of the oven, then let the cookies cool on the pan.