Even if you don't have to eat gluten-free, you're going to love these homemade oatmeal cream pies. You can use regular oats if you're not on a gluten-free diet (if you are, be sure to buy purity protocol certified gluten-free oats, though, since oats can be contaminated in processing with gluten ingredients). The oats and oat flour really give them the flavor of the original snack cakes. And if you're not able to find oat flour, it's so easy to make your own using your food processor to reduce whole oats down to a flour consistency. It only take a few minutes!
Preheat oven to 350 degrees F and line cookie sheet with parchment paper.
In mixing bowl, combine sugar, sunflower seed butter, egg, honey and vanilla and stir by hand until smooth.
Add dry ingredients to the mixture in mixing bowl and stir until no dry ingredients remain visible.
Spoon batter onto parchment lined pan by the tablespoon, spacing 2 inches apart.
Moisten fingers with a little water and pat mounds of batter into even circles, about 2 to 2.5 inches around. (Don't over-flatter, just make nice even cookie rounds.)
Bake 7-9 minutes, until tops appear just dry and cookies puff slightly, then remove from oven and cool completely on the pan.
Use a spatula to remove cookies from the pan to a serving tray, placing half of the cookies with tops down (flat side facing up).
To assemble, spoon (or pipe) approximately 2 teaspoons marshmallow creme onto the cookies with flat side up, then top each one with another cookie (flat side down toward the filling, to make sandwiches.