Thin and Crispy Chocolate Chip Cookies

Before you start

A crisp cookie is designed to spread. Melted butter loosens the dough, a higher share of white sugar melts and then hardens into a glassy, crunchy structure as it cools, and a little milk thins the dough further. Brown sugar is kept to a small amount because its molasses holds moisture, which is the opposite of what you want here.

The other half of the job is the bake. These cookies are baked at a moderate temperature for longer than usual, until they are golden all the way to the center, so that the moisture cooks out. Mini chocolate chips spread the chocolate evenly through a thin cookie without leaving thick lumps that stay soft.

Ingredients

• 170 g (¾ cup) unsalted butter — melted and cooled until just warm
• 200 g (1 cup) granulated sugar
• 50 g (¼ cup packed) light brown sugar
• 1 large egg
• 2 tbsp whole milk
• 1 tsp vanilla extract
• 190 g (1½ cups plus 1 tbsp, spooned and leveled) all-purpose flour
• ¾ tsp baking soda
• ½ tsp fine salt
• 170 g (1 cup) mini semisweet chocolate chips

Method

1. Heat the oven to 175°C (350°F) with a rack in the center and line two sheets with parchment.
2. Whisk the melted butter with the granulated and brown sugars for about 30 seconds until smooth. Whisk in the egg, milk and vanilla until glossy.
3. Add the flour, baking soda and salt and stir with a spatula just until no dry flour remains. Fold in the mini chips. The dough will be soft and loose.
4. Scoop 25 g portions (about 1½ tbsp) and space them 7.5 cm (3 in) apart, no more than 10 to a sheet; they spread a lot. Flatten each one slightly with your fingers.
5. Bake one sheet at a time for 12 to 14 minutes, until the cookies are flat and evenly golden brown from edge to center, with no pale or shiny spots in the middle.
6. Cool on the sheet for 3 minutes, then move to a rack. They feel soft while hot and turn crisp within 10 to 15 minutes as the sugar sets.

Tips for success

• Do not chill this dough. Cold dough spreads less, and these cookies need to spread.
• If one cookie comes out bendy after cooling, return the whole batch to the oven for 2 minutes.
• For extra-thin cookies, lift the sheet and drop it on the oven rack once at the 8-minute mark to flatten the puff.

Substitutions

Mini chocolate chips

Finely chopped bar chocolate also works and gives thin streaks of chocolate. Regular chips leave thick spots that stay soft.

Light brown sugar

Use all granulated sugar (250 g total) for the crispest, palest cookie with a simple butter flavor.

Whole milk

Water works the same way for spread; the cookies brown slightly less.

Variations

Toffee crunch cookies

Replace half the chocolate chips with 85 g chopped toffee bits.

Oat crisps

Replace 40 g of the flour with quick oats for a lacier, nubbly texture.

Troubleshooting

Cookies are chewy instead of crisp

They were underbaked or stored with something soft. Bake until evenly golden all over and keep them in their own airtight tin.

Cookies ran into each other

The dough portions were too close or too large. Use 25 g portions and leave 7.5 cm between them.

Edges burned before centers browned

The oven is too hot or the sheet is dark. Check the temperature with a thermometer and use a light-colored sheet.

Storage

Keep the cookies in an airtight tin at room temperature for up to 1 week. If they soften in humid weather, recrisp them at 160°C (325°F) for 4 to 5 minutes and cool on a rack.

Safety notes

Do not taste raw dough or batter made with flour and egg. Contains wheat, egg, milk and soy.