Combine the dry ingredients: In a medium bowl, whisk together the flour, baking soda, and salt until evenly combined.

Cream the butter and sugars: In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar on medium speed for 2 to 3 minutes. The mixture should look creamy, slightly fluffy, and lighter in color.

Add the eggs and vanilla: Beat in the eggs one at a time, mixing until each is incorporated. Add the vanilla and scrape down the sides and bottom of the bowl.

Add the dry ingredients: Mix the flour mixture into the wet ingredients on low speed just until a thick dough forms. Stop when only a few small flour streaks remain.

Fold in the s’mores mix-ins: Reserve 1/2 cup (25 g) of the mini marshmallows for topping. Fold the semisweet chocolate chips, chopped milk chocolate, graham cracker pieces, and remaining 1 cup (50 g) marshmallows gently into the dough.

Chill the dough: Cover the bowl and refrigerate for 1 hour. The dough should feel firm enough to scoop and hold a tall mound.

Prepare the oven and pans: Preheat the oven to 350°F (175°C). Line two large baking sheets with parchment paper.

Portion the cookies: Scoop approximately 3 tablespoons of dough, about 3 ounces (85 g), per cookie. Shape each portion into a tall mound rather than a flat ball.

Arrange on the baking sheets: Place 6 to 8 dough portions on each prepared baking sheet, leaving at least 3 inches (7.5 cm) between them.

Bake the first stage: Bake one sheet at a time on the center rack for 9 minutes. The cookies should have spread slightly, but the centers will still look underbaked.

Add the marshmallow topping: Carefully remove the pan from the oven. Press several pieces of the reserved mini marshmallows into the top of each cookie. Add optional extra chocolate chips and graham cracker pieces at this stage, if using.

Finish baking: Return the cookies to the oven and bake for another 3 to 5 minutes. The edges should be golden and set, while the centers remain soft. The marshmallows should look puffed and lightly toasted in spots.

Reshape if needed: Immediately after baking, use the edge of a large round cookie cutter or spoon to gently nudge any uneven edges into a round shape. Do this while the cookies are still very soft.

Cool on the baking sheet: Let the cookies stand on the hot baking sheet for 10 minutes. The centers will continue setting as they cool.

Cool completely: Transfer the cookies carefully to a wire rack and cool for another 20 minutes. Repeat with the remaining dough.