Cake: Mix yeast, salt, 4 T sugar, and 3/4 cup flour. Add butter to milk. Heat until very warm (120-130 degrees F.). Gradually add milk to flour mixture. Beat for 2 minutes. Add egg and 1/2 cup flour. Beat with an electric mixer on high speed for 2 minutes. Mix in enough flour to form a soft dough. Knead for 5 to 10 minutes, until dough is shiny and elastic. Place in greased bowl and let rise for 1 hour or until doubled in bulk. Pat dough into well-greased 10-inch springform pan pressing the dough 1 1/2 inches up the sides of the pan. Filling: Toss apples with lemon juice, cinnamon, 1/4 cup sugar, and 2 T of flour. Arrange in rows on top of the dough. Beat together cream cheese, 1/2 cup sugar, and egg. Spread over apples. Let rise in warm place for 1 hour. Bake at 350 degrees F. for 30 minutes. Best when served warm.