Brown the butter: Place ½ cup (113g) unsalted butter in a light-colored saucepan over medium heat. Cook until it melts, foams, and golden brown specks appear. Immediately pour into a large heat-safe bowl. Cool for 10-15 minutes.
Whisk dry ingredients: In a medium bowl, whisk together 1½ cups (190g) flour, ½ teaspoon baking soda, and ½ teaspoon salt. Set aside.
Cream butter and sugars: To cooled browned butter, add ¾ cup (150g) brown sugar and ¼ cup (50g) granulated sugar. Beat on medium speed for 2-3 minutes until combined and slightly fluffy.
Add wet ingredients: Add room temperature egg and 1½ teaspoons vanilla extract. Beat until smooth and glossy, scraping bowl as needed.
Combine: With mixer on low, gradually add dry ingredients. Mix just until no flour streaks remain. Do not overmix.
Crush Oreos: Place Oreos in a zip-top bag and crush with a rolling pin until you have a mix of fine crumbs and chunks.
Add mix-ins: Using a rubber spatula, fold in 1 cup (175g) chocolate chips and crushed Oreos until evenly distributed.
Chill: Cover dough and refrigerate for at least 1 hour.
Preheat and prep: Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
Scoop: Scoop dough into 2-tablespoon balls (about 35g each). Place on prepared sheets, 2 inches apart.
Bake: Bake for 10-12 minutes until edges are set and lightly golden. Centers will look soft.
Cool: Let cookies cool on baking sheet for 5-10 minutes. Transfer to wire rack.
Serve: Enjoy warm or at room temperature.
