In the bowl of a stand mixer, combine the brown sugar and salt using the whisk attachment. Set aside.

To brown the butter: In a saucepan over medium-high heat, melt the butter. After several minutes, the butter will sizzle and may spatter. Continue to cook the butter, swirling the pan regularly, for about 5 to 7 minutes, until it’s a dark golden brown color and brown bits start collecting at the bottom of the pan; the butter will have stopped sizzling and may also have a layer of foam on the surface.

Once the butter is browned, immediately pour it over the sugar mixture (be sure to scrape out the brown bits at the bottom) and whisk vigorously to combine; this helps dissolve the sugar slightly and creates the shiny surface of the baked cookies. (The mixture will stay lumpy and won’t become smooth at this point.) Set the empty saucepan aside to cool slightly.

To make the tangzhong: In the same saucepan used to brown the butter, combine the milk with 3 tablespoons bread flour and whisk until no lumps remain.

Place the saucepan over low heat and cook the mixture, stirring regularly with a whisk and then a flexible spatula, until it’s thickened, paste-like, and starts to come together into one mass, about 2 to 3 minutes.

Remove from the heat and transfer directly to the bowl with the butter and sugar. Whisk until mostly smooth; some lumps of the tangzhong mixture are okay.

Add the eggs and vanilla and continue whisking until smooth.

Add the remaining 2½ cups plus 1 tablespoon bread flour to the bowl with the butter and sugar, then add the baking powder and baking soda. Switch to a paddle attachment and mix until well combined and no dry spots remain.

Place the bowl, uncovered, in the refrigerator and allow it to cool for 10 to 15 minutes.

Remove the dough from the refrigerator and fold in the chocolate chips. Cover the bowl and return to the refrigerator for 24 to 72 hours to allow the flavors to intensify.

To bake the cookies: When you’re ready to bake, remove the chilled cookie dough from the refrigerator and let it rest at room temperature for about 10 to 15 minutes to allow it to warm up slightly. Meanwhile, preheat the oven to 350°F with a rack in the center.

Scoop the dough into 85g to 90g portions – mounds of dough should be about 2¼” in diameter.

Arrange the cookie dough balls on parchment-lined baking sheets, spacing them 3″ to 4″ apart. Five, maybe six dough balls, will fit on a half-sheet pan.

Bake the cookies for 18 to 22 minutes, until the edges are set and the cookies are browned, rotating the pan halfway through baking to ensure even browning. Remove the cookies from the oven and let them rest on the baking sheets until cool enough to handle, at least 15 minutes.