Whisk together flour, baking soda, and salt in a medium-sized bowl. About two minutes, or until well blended, whip the butter, peanut butter, brown and granulated sugar in the bowl of a hand held or stand mixer.
Beat in the vanilla and then the egg until well blended. Brush the bowl's sides down. Gradually add the dry ingredients to the mixer set on low.
Stir the marshmallows into the mixture with a wooden spoon or spatula after the chocolate chips. To make domes out the dough, use an ice cream scoop; set them on a small baking sheet and refrigerate.
Heat oven to 350 degrees Fahrenheit. Leaving two to three inches between each cookie dough ball, place six on each baking sheet. At a time, bake one plate of cookies.
– Serving: 1cookie – Calories: 316kcal – Carbohydrates: 39g – Protein: 4g – Fat: 16g – Saturated Fat: 8g – Polyunsaturated Fat: 1g – Monounsaturated Fat: 4g – Trans Fat: 0.4g – Cholesterol: 40mg – Sodium: 216mg – Potassium: 82mg – Fiber: 1g – Sugar: 25g – Vitamin A: 337IU – Vitamin C: 0.1mg – Calcium: 34mg – Iron: 1mg