Preheat oven to 350℉. Line two cookie sheets with parchment paper and set aside.
In a large bowl, whisk together flour, baking soda, salt, cinnamon, and cloves. Set aside.
In the bowl of a stand mixer (or using a hand mixer), beat butter, brown sugar and granulated sugar on medium-high speed until light and creamy, about 1 minute. Add eggs and vanilla. Beat until combined. Scrape down the sides and the bottom of the bowl.
With the mixer on low, slowly add the dry ingredients to the wet ingredients. Mix just until combined (avoid over mixing—it’s okay if there are a few flour pockets.) Add oats and mix until incorporated.
Scoop about 2 tablespoons of dough and place on prepared cookie sheet. Space the balls of dough at least 3 inches apart as the cookies will spread. Bake for 10 to 12 minutes or until the edges are light brown. Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Filling
While the cookies cool, add butter to the bowl of a stand mixer (or use a hand mixer), and beat on medium-high speed until light in color, about 3 minutes. With the mixer on low, gradually add confectioners’ sugar and mix until well combined, about 1 minute. Add 1 tablespoon of heavy cream, vanilla, and salt. Beat on medium-high speed until fluffy. If the filling is too thick, add another tablespoon of heavy cream.
Assembly
Once the cookies are cooled, pipe or spread crème filling on the flat side of half the baked cookies. Top with remaining cookies to form sandwiches. Enjoy!
Notes
Quick oats work best for a chewy, yet smoother cookie texture, which is essential for spreading the creme filling. If you only have old fashioned oats on hand, pulse them in the food processor for 5 seconds before using.Store leftover sandwich cookies at room temperature for up to 2 days, or in the refrigerator for up to 5 days.Freeze individual pies for up to 1 month. Wrap each pie tightly in plastic wrap, then place in a zip-top freezer bag.