Reduce your apple cider over medium heat until it's thick and syrupy—about ¾ cup should turn into 3–4 tablespoons.
Beat the cream cheese until smooth. Add sugar, flour, and salt, and keep beating until it's fluffy (like your favorite pillow).
Mix in the sour cream and reduced cider. Add the eggs one at a time, beating just enough to incorporate.
Pour the batter into the crust-lined pan. Smooth the top like you're icing a cake for your childhood hero.