To prepare the cookie dough:

1. In the bowl of a stand mixer fitted with the paddle attachment, cream the butter, brown sugar, syrup, and vanilla until fluffy, about 1 minute.
2. In a separate large bowl, combine the flour, graham cracker crumbs, kosher salt, baking powder, baking soda, and ground cinnamon.
3. With the mixer speed set to low, work in batches to add the dry ingredients to the wet ingredients until fully combined. Add the milk slowly until the mixture comes together.
4. Arrange a large sheet of plastic wrap onto a flat surface. Turn out the dough onto the plastic, and form the dough into a large disc. Wrap the edges of the plastic wrap tightly around the dough. Refrigerate the dough for 1 hour.
5. Preheat the oven to 325 degrees F.
6. Turn the dough out onto a lightly floured work surface. Allow dough to sit for 10 minutes so it is easier to work. Roll the dough until it is 1/4-inch thickness. Using a 3-inch round cookie cutter, cut 12 cookie halves. Place each half onto a cookie sheet.
7. Bake the cookies for 10-12 minutes. Allow cookies to cool on the cookie sheet for 15 minutes. Carefully transfer the cookies to a cooling rack, and allow to cool completely.
8. Spoon approximately 1/4 cup of marshmallow creme onto a cookie half. Spread the creme until it nearly reaches the edges of the cookie. Top with a second cookie half and press down slightly. Dress up the edges with an offset spatula as needed.
9. Place assembled cookie sandwiches onto a cookie sheet, and refrigerate for at least 15 minutes.

To prepare the chocolate coating:

1. Melt the chocolate in a double boiler. Once the chocolate has melted and is smooth, remove the pan from heat. Once the chocolate is warm to the touch, carefully whisk in the oil.

To assemble the moon pies:

1. Line a cookie sheet with parchment paper.
2. Use two forks to gently lower a cool cookie sandwich into the melted chocolate. Flip the cookie sandwich until it is fully coated. Transfer the coated cookie to the prepared cookie sheet. Allow the cookies to stand until the chocolate shelly fully hardens.