Preheat the oven to 350°F. Line a baking sheet with a silicone liner.

To make the cookies, a large bowl, stir or beat together the egg, oil, brown sugar, yogurt, and caramel.

In a separate bowl, combine the flour, baking powder, and salt.

Add the dry ingredients to the wet ingredients in two additions, mixing thoroughly after each to incorporate and achieve a smooth batter without lumps.

Transfer the dough to a piping bag without a tip (or use a
sturdy resealable plastic bag and cut one of the corners off to use as a piping bag).

Pipe the batter onto the silicone liner to make circles about 2 inches across. Leave a couple of inches between cookies to allow for spreading.

Bake for 15 to 20 minutes. Remove from the oven and transfer the cookies to a wire rack to cool completely.

While the cookies are cooling, make the filling.

Cream together the butter and powdered sugar. Add the caramel,
vanilla, and pinch of salt and mix to incorporate. Add the mascarpone and mix well.

Apply the filling to the flat side of half of the cookies (you can use a piping bag or spread with a knife). Add the remaining cookies to complete the sandwiches.

Serve immediately or refrigerate until ready to serve.