1. Slice 1/2 cup of the butter and place it into a large mixing bowl or the bowl of a stand mixer. Add the remaining 1/2 cup of butter to a saucepan over medium heat.

2. Allow the butter to melt and bubble. Once it begins to foam quietly and turns amber with a nutty aroma, remove it from the heat.

3. Pour the browned butter over the unbrowned butter in the mixing bowl. Scrape in the brown bits from the pan and stir to combine until fully melted.

4. In a separate bowl, whisk together flour, baking soda, cream of tartar, salt, and cinnamon.

5. Once the butter mixture cools, add dark brown sugar and granulated sugar. Beat for 2–3 minutes until smooth and creamy.

6. Add maple syrup, eggs, and vanilla extract. Mix on medium-high speed until the mixture becomes pale and fluffy.

7. Scrape down the sides of the bowl and mix again briefly.

8. Add the dry ingredients to the wet ingredients. Mix on low speed or fold with a rubber spatula until combined.

9. Fold in mini marshmallows and dark chocolate chips until evenly distributed.

10. Refrigerate the dough uncovered for 1 hour.

11. After chilling, scoop the dough using a 1/4-cup measuring cup. Roll each ball in the cinnamon-sugar coating and shape into tall mounds.

12. Place on a tray lined with parchment paper and refrigerate while preheating the oven to 350°F (177°C).

13. Arrange 5 cookies per baking sheet lined with parchment paper. Bake for 14–16 minutes until edges are golden and centers are puffed.

14. If cookies lose shape, gently nudge the edges with a fork immediately after baking.

15. Cool on the baking sheet for 5 minutes before transferring to a wire rack.

16. Serve warm for a gooey center or at room temperature for a chewy texture.