1-Step 1: Cream the Butter and Sugars Begin by beating the room temperature butter, white sugar, and light brown sugar in a large mixing bowl using a stand mixer or hand mixer. Beat on medium speed for 3-4 minutes until the mixture becomes light, fluffy, and noticeably paler in color. This aeration creates pockets of air that help the cookies spread properly and develop those desirable crisp edges. The mixture should look whipped and creamy before moving forward.

2-Step 2: Add Eggs and Flavor Scrape down the sides of the bowl with a rubber spatula to ensure even mixing. Add the room temperature egg, additional egg yolk, and vanilla extract to the creamed butter mixture. Beat on medium speed for about 1 minute until fully combined and the mixture looks smooth and glossy. The extra yolk is what gives these gooey marshmallow graham cookies their signature chewy texture.

3-Step 3: Incorporate Dry Ingredients With the mixer on low speed, gradually add the all-purpose flour, baking powder, baking soda, kosher salt, and Dutch processed cocoa powder to the wet mixture. Mix just until combined, scraping the sides of the bowl as needed to catch any dry pockets. Avoid overmixing at this stage, as it can develop gluten and result in tough cookies. The dough will be thick and fudgy, similar to brownie batter consistency.

4-Step 4: Fold in the S’mores Mix-ins Remove the bowl from the mixer and use a rubber spatula to fold in the crushed graham crackers, chopped chocolate, and mini marshmallows by hand. Work gently to distribute the mix-ins evenly without crushing the marshmallows or overworking the dough. Each scoop should contain a balanced mixture of all three components for that authentic s’mores experience in every cookie.

5-Step 5: Chill the Dough Cover the mixing bowl with plastic wrap or transfer the dough to an airtight container. Chill in the refrigerator for 45-60 minutes to firm up the butter and make scooping easier. This crucial step prevents excessive spreading during baking and helps the s’mores cookies with marshmallows maintain their thick, chewy shape. If you’re short on time, you can freeze the dough for 20-25 minutes instead.

6-Step 6: Preheat and Prepare Baking Sheets While the dough chills, preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper for easy cleanup and to prevent sticking. Having the oven ready at the right temperature ensures consistent baking results from batch to batch.

7-Step 7: Scoop and Shape Using a 3-tablespoon cookie scoop or your hands, portion the chilled dough into balls and place them on the prepared baking sheets, leaving about 2 inches between each cookie for spreading. For thicker cookies, press a few extra marshmallows and chocolate chunks onto the tops of each dough ball before baking. This creates those beautiful, bakery-style tops with visible mix-ins peeking through.

8-Step 8: Bake to Perfection Bake one sheet at a time in the preheated oven for 8-10 minutes. The cookies are done when the edges look set and slightly cracked while the centers still appear slightly underdone. They will continue to firm up as they cool. Keep the remaining dough refrigerated between batches to maintain consistent results. Bake time may vary slightly depending on your oven, so start checking at 8 minutes.

9-Step 9: Cool and Serve Allow the baked chocolate graham marshmallow treats to cool directly on the baking sheet for at least 5-10 minutes before transferring to a wire rack. This resting period lets the cookies set properly so they hold their shape when moved. For perfectly round cookies, gently shape them with a biscuit cutter or the rim of a mug while they’re still warm. Serve warm for that fresh-from-the-oven experience with melty chocolate centers.