Ingredients

1 ¾ cups (220 g) all-purpose flour

1/2 cup (40 g) unsweetened cocoa powder

1 teaspoon baking soda

1/4 teaspoon salt

1/2 cup (115 g) unsalted butter, softened

3/4 cup (150 g) granulated sugar

1/2 cup (100 g) packed light brown sugar

1 large egg

1 teaspoon vanilla extract

1/2 cup (90 g) semi-sweet chocolate chips

1 cup (50 g) mini marshmallows

1/3 cup (60 g) marshmallow fluff (optional)

Instructions

Step 1: Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

Step 2: In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt until well combined.

Step 3: In a large bowl, cream the softened butter with the granulated sugar and brown sugar until the mixture is light and fluffy, about 2–3 minutes.

Step 4: Beat in the egg and vanilla extract until the batter is smooth and fully combined.

Step 5: Gradually add the dry ingredients to the wet ingredients in two to three batches, mixing just until combined. Avoid overmixing.

Step 6: Gently fold in the semi-sweet chocolate chips.

Step 7: Fold in the mini marshmallows and, if using, the marshmallow fluff carefully to keep some swirl patterns and avoid melting.

Step 8: Scoop tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Step 9: Bake for 8–10 minutes, until the edges are set but the centers remain soft.

Step 10: Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Tips & Variations

For extra gooey marshmallows, add a little more marshmallow fluff or swap mini marshmallows for larger ones chopped in half.

Use dark chocolate chips instead of semi-sweet for a richer flavor contrast.

If you prefer crispier cookies, bake an additional 1–2 minutes, watching carefully to avoid burning.

For a festive touch, add chopped nuts or a sprinkle of sea salt on top before baking.

FAQs

Can I use different types of chocolate chips?

Yes, you can substitute semi-sweet chocolate chips with milk chocolate, dark chocolate, or even white chocolate chips depending on your preference. Each will change the flavor slightly.

Will the marshmallows melt too much during baking?

The mini marshmallows and marshmallow fluff are folded in carefully to maintain some texture and swirl patterns. Baking just until edges set helps keep them gooey without fully melting away.