Preheat oven to 350°
Combine melted butter, brown sugar, eggs and vanilla in a bowl. Mix well.
In a separate bowl, combine flour, baking soda and salt. Slowly add to the butter mixture.
Add the oatmeal, walnuts and raisins. Mix well.
Drop the batter (1 tablespoon at a time) onto ungreased cookie sheets. Flatten each cookie slightly with the back of a spatula.
Bake 12 minutes until golden and firm. Remove cookies to a cake rack to cool (feel free to sample a few cookies... there will still be plenty for the Sneetch Treats!)
Once cookies have cooled, put a square of chocolate onto each cookie.
Heat up your grill (or smoker... or fire pit... or oven).
Place marshmallows on skewers or BBQ forks. Slowly roast marhmallows over the grill until they're golden on each side.
Carefully slide marshmallows off of forks and onto the chocolate-covered cookies. Place another cookie on top of the Marshmallow.