Preheat the oven to 350°F. Line a baking sheet with parchment and set aside.
In a large mixing bowl, mix together the softened butter, sugars, egg, and vanilla extract until well combined.
In another bowl, whisk together flour, baking soda, and salt.
Fold the dry ingredients into the wet. Just before the flour mixture is all combined, add the marshmallows (reserve about ¼ cup), and fold everything together.
Use a medium cookie scoop to scoop the dough onto your parchment.
Use the reserved marshmallows to press into the tops of the cookies.
Bake for 8-10 minutes.
Allow the cookies to cool for 5 minutes on the baking sheet, and move to a cooling rack.
Notes
Room Temperature: Store leftover Magical Marshmallow Cookies in an airtight container at room temperature for up to 4 days. To keep them soft, place a slice of bread in the container—it helps retain moisture.Freezer: Place the cookies in a sealed freezer bag or airtight container for up to 3 months.Thaw and Reheat: When ready to eat, let them thaw at room temperature or warm them in the microwave for 10-15 seconds to restore their soft, gooey texture.