1. Prep & Preheat
Preheat oven to 350°F (175°C).
Line baking sheets with parchment paper (prevents sticking).
2. Make the Dough
In a large bowl, combine brownie mix, eggs, and oil. Stir until no dry streaks remain (dough will be thick).
Fold in mix-ins (if using).
3. Scoop & Shape
Use a 1.5-tbsp cookie scoop (or a spoon) to portion dough.
Roll into balls, then flatten slightly (cookies spread a little but stay thick).
Pro tip: For stuffed cookies, press a 1/2 tsp Nutella into the center of each ball and seal the dough around it.
4. Bake to Perfection
Bake for 9–11 minutes (edges should look set; centers will be soft).
Let cool on the pan for 5 minutes before transferring to a rack (they firm up as they cool).
Expert Tips for the Best Cookies
🔥 Underbake slightly – They’ll continue to cook on the hot tray.
🍫 Double the chocolate – Toss in chocolate chunks and chips.
🧂 Add flaky salt – A sprinkle on top balances the sweetness.
⏳ Storage – Keep in an airtight container for up to 5 days (or freeze dough balls for later!).