Preheat the oven to 350 degrees F. Lightly grease a 9-inch round cake pan. Place the butter and honey in a small pot or dish and melt together on the stove or in the microwave. Pour into the cake pan. Toss the apple slices with lemon juice, then arrange in spiral-like fashion into the bottom of the cake pan. Combine flour, salt and baking powder in a bowl, then set aside. In another bowl, beat butter and sugar until light. Beat in eggs and vanilla. Add flour mixture to butter mixture alternately with milk. Spoon the batter into cake pan. Bake 40-45 minutes, or until cakes springs back when lightly touched. Remove from oven and invert on a serving platter. Let cake stand 10 minutes before removing pan. Serve warm or at room temperature.