Preheat your oven to 350°F (175°C). This ensures the oven is hot enough to bake your cookies evenly and achieve a perfect golden color.
Beat softened butter with both sugars until light and fluffy—about 2-3 minutes. Make sure the butter is at room temperature to keep the cookies soft and chewy.
Add the eggs individually, mixing thoroughly after each addition.
Stir in vanilla extract for extra flavor and richness.
In a separate bowl, whisk together flour, baking soda, and salt to distribute the ingredients evenly.
Slowly combine the dry mixture with the wet ingredients, stirring gently. Stop as soon as everything is mixed, leaving the dough soft and a bit sticky.
Gently fold in the chocolate chips and marshmallows, being careful not to break them up.
Scoop the dough into balls about 1 to 1 ½ inches in diameter and place them on a lined baking sheet. Leave space between each cookie for them to spread.
Bake for 10 minutes, or until the edges turn golden while the centers remain slightly soft. They will firm up once cooled.
Allow the cookies to sit on the baking sheet for 5 minutes before placing them on a wire rack to cool fully. Enjoy!