Brown the butter by melting unsalted butter in a medium saucepan over medium heat, stirring frequently until golden brown, about 5-7 minutes. Allow to cool for 10 minutes.

Mix dry ingredients by whisking together all-purpose flour, baking soda, salt, espresso powder, and Vietnamese cinnamon in a large bowl.

Combine wet ingredients by mixing cooled browned butter with granulated sugar, dark brown sugar, and light brown sugar until creamy. Add room temperature egg and vanilla extract; blend until smooth.

Combine mixtures by gently folding dry ingredients into wet ingredients until just integrated, avoiding overmixing.

Incorporate chocolate chips by adding dark chocolate chips to the dough and mixing gently.

Chill the dough by covering with plastic wrap and refrigerating for at least 45 minutes.

Preheat oven to 350°F (177°C) and line two baking sheets with parchment paper.

Scoop cookies using a 2-tablespoon cookie scoop onto prepared sheets, leaving 2 inches between each.

Bake for 14-16 minutes or until edges are lightly golden and centers are set.

Cool for 10 minutes on baking sheet before transferring to a cooling rack for another 10 minutes.