Ultimate brown butter coffee toffee cookies with rich, nutty browned butter, bold espresso kick, and crunchy toffee bits. Perfect chewy centers with crispy edges.
Melt butter in a light-colored saucepan over medium heat. Continue cooking, swirling occasionally, until milk solids turn nutty brown and smell fragrant, about 5-8 minutes. Pour into heatproof bowl and let cool to room temperature, about 15-20 minutes.
In a medium bowl, whisk together flour, baking soda, baking powder, and salt. Set aside.
In a large mixing bowl, combine cooled browned butter (at room temperature), light brown sugar, and granulated sugar. Beat with electric mixer on medium speed for 2-3 minutes until well combined.
Add egg, egg yolk, vanilla extract, and instant espresso powder to butter-sugar mixture. Beat until smooth and creamy, about 1-2 minutes.
Pour dry ingredients into wet ingredients and mix on low speed until just combined. Fold in toffee bits with a spatula until evenly distributed.
Cover bowl with plastic wrap and refrigerate dough for at least 1 hour (or up to 24 hours for even better flavor). Minimum 30 minutes if in a rush.
Preheat oven to 375°F (190°C). Line two baking sheets with parchment paper.
Scoop rounded tablespoons of chilled dough onto prepared baking sheets, leaving 2 inches between each cookie.
Bake for 10-12 minutes until edges are golden brown but centers still look soft and slightly pale.
Let cookies cool on baking sheet for 5 minutes before transferring to wire rack to cool completely.
Notes
Do not walk away from browning butter as it can burn quickly. Use light-colored pan to monitor color change.
Chilling dough for at least 1 hour is ideal for thicker, chewier cookies and enhanced flavors. Minimum 30 minutes if rushed.
Instant espresso powder is different from ground coffee. Do not substitute brewed coffee.
For extra flavor, add pinch of sea salt on top right after baking.
Use cookie scoop for uniformly sized cookies that bake evenly.
Do not overbake. Cookies continue to set on hot baking sheet after removal from oven.
At high altitude (above 3,500 feet), reduce baking soda to ¾ teaspoon.
This recipe doubles easily. Brown butter in batches for best control.