For the Cookies:

1. Preheat oven to 350°F. Line a large baking sheet with parchment paper and set aside.
2. Whisk together the flour, oats, baking soda, baking powder, and salt. Using a stand or handheld mixer, beat the butter, peanut butter, and both sugars on medium speed until light and fluffy. Add the egg and vanilla extract. Mix until combined. With the mixer on low speed, slowly add the dry ingredients, mixing just until combined.
3. Take about 1 tablespoon of dough and roll into a cookie ball. Place on prepared baking sheet, leaving about 2 inches between the cookies. Bake for 10-12 minutes, or until the cookies are golden and the edges are set. Let the cookies cool on the baking sheet for 5 minutes then transfer them to a wire rack to cool completely.
4. Make the filling while the cookies are baking/cooling.

For the Salted Caramel Filling:

1. Follow the linked instructions above.
2. Fill each cookie sandwich evenly with the filling.

For the Chocolate Dip:

1. Place the formed cookie sandwiches on a baking sheet and place in the freezer for at least 10 minutes before dunking in the chocolate.
2. While the cookies are in the freezer, place the chocolate in a heatproof bowl. Heat the cream in the microwave until hot and then pour over the chocolate. Stir until completely melted and smooth. Dip each semi-frozen cookie sandwich into the ganache, place on a parchment-lined baking sheet, and sprinkle with sea salt while still tacky. Continue until all the cookies have been dunked in the chocolate and sprinkled with salt. Allow the cookies to set for at least 10 minutes.
3. Leftover cookies are best stored in an airtight container in the fridge.