In a large bowl, whisk together flour, granulated sugar, baking powder, salt, and pie spice.

In a small bowl, whisk together buttermilk, cider, egg yolk, melted butter, and vanilla until well combined. Stir in apple. Add buttermilk mixture to flour mixture, whisking until just combined.

In a medium bowl, beat egg whites with a mixer at medium-high speed until stiff peaks form. Gently fold egg whites into batter in three additions.

Heat a nonstick aebleskiver pan over medium-low heat. Brush melted butter into wells of hot pan. Using a 2-tablespoon spring-loaded scoop, scoop batter (about 32 grams each) into prepared wells. Cook until batter begins to bubble around edges, 1 to 2 minutes. Using long, thin wooden skewers, gently lift and turn each ball about 90 degrees, letting batter that is on top move to bottom of pan. Once batter bubbles again, gently lift and turn another 90 degrees. Repeat procedure until ball is golden brown on all sides and cooked through. Remove from pan, and repeat with remaining batter. Serve warm with apple butter. Garnish with confectioners’ sugar, if desired.