Oatmeal Sandwich Cookies With Spiced Marshmallow Filling

These oatmeal cookies are so good on their own, but the whole world loves an oatmeal sandwich cookie with marshmallow filling. Adding some of the cookie spices to the marshmallow filling really enhances the flavor. I'm normally not fussy about cookie size, but I like to use a medium-sized cookie scoop here. The cookies are already craggy and varied, so having roughly the same diameter helps to keep the sandwiches even.

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% Daily Values based on a 2,000 calorie diet

Step 1

Preheat the oven to 350° F (175°C). Line two baking sheets with parchment paper.

Step 2

To make the cookies, in a large bowl, with a wooden spoon, beat 10 tablespoons (140 g) butter and the brown sugar until light and creamy, about 3 minutes. Add the egg yolk, 1 teaspoon vanilla and the molasses, beating for 1 minute. Sprinkle ½ teaspoon salt, the baking soda, ½ teaspoon cinnamon, ½ teaspoon cardamom and ¼ teaspoon cloves over the dough. Stir for 1 minute, or until the spices are well incorporated. Gently stir in the flour and oats, until just combined.

Step 3

Using a cookie scoop, form balls with about 1½ tablespoons (21 g) of the dough. Drop the cookie dough onto the prepared cookie sheets, leaving 2 inches (5 cm) of space between the dough balls. Bake for about 10 minutes, or until the edges are browned and the tops of the cookies look set and dry. You want a crispy, fully baked cookie since it will soften once it sits with the marshmallow filling. Allow the cookies to cool for 10 minutes.

Step 4

Transfer to a rack and cool completely.

Step 5

For the filling, in a medium bowl, beat 3 tablespoons (42 g) of butter with an electric mixer until light and fluffy. Add the marshmallow fluff, milk and ½ teaspoon vanilla. Beat for 2 minutes, or until well combined. Sprinkle ½ teaspoon cinnamon, ¼ teaspoon cardamom, a pinch of cloves and a pinch of salt over the filling. Beat to combine.

Step 6

Add the powdered sugar, beating until a light, stiff filling forms.

Step 7

You can add more milk if it thickens too quickly, but you want the filling to be fairly thick so it doesn't ooze out of the cookies.

Step 8

To assemble, frost the bottom side of half the cookies and sandwich another cookie on top of each. Store in an airtight container in the fridge for up to 1 week.