Sticky, sweet, with a touch of apple-y tartness, these doughnuts are everything we know and love about caramel apples. They're moist, cakey, and the ideal sweet and salty fall treat to enjoy alongside a cup of hot tea or coffee.
Preheat the oven to 350°F. Lightly grease a standard doughnut pan. (See "tips," below, for an alternative pan.)
In a medium bowl, whisk together the flour, buttermilk powder, baking powder, salt, apple pie spice, and sugar until well blended. Stir in the diced apple. Set aside.
In a separate small bowl or measuring cup, whisk together the melted butter, egg, boiled cider, water, and vanilla.
Fold the wet ingredients into the dry ingredients until the batter is evenly moistened and smooth (except for the apple pieces).
Fill the wells of the doughnut pan nearly to the rim.
Bake the doughnuts for 12 to 14 minutes, or until a toothpick inserted into the center of one comes out clean.
Remove the doughnuts from the oven, and loosen their edges.
After about 5 minutes, transfer them to a rack to cool completely.
To make the caramel: Combine the milk and caramel in a small saucepan set over medium heat or in a microwave-safe dish.
Heat, stirring occasionally, until the caramel melts and the mixture is smooth.
Spread the doughnuts with caramel (or dip their tops in caramel), sprinkle them with sea salt, and return them to the rack until the caramel is set.
