Place an oven rack on the second highest position and preheat oven to high broil.
Place 10 Oreos (as original recipe is written // adjust if altering batch size) on a baking sheet and top with a marshmallow (or several minis).
Broil on high for 1-3 minutes, watching closely, until toasted and deep golden brown.
Remove from oven and top each with 1/2 Tbsp peanut butter (briefly warm in microwave if not pourable), then top with second Oreo.
*I didn't coin the term S'moreo! Not sure who did, but they're smart. I first saw it on Top with Cinnamon *Vegan marshmallow brands I'm currently aware of: Dandies *Nutrition information is a rough estimate.