Apple Charlotte

Born from thrift—uses up day-old bread and windfall apples. Tastes like fall. · 6 firm tart apples (Granny Smith), peeled and sliced · ½ cup sugar · 1 teaspoon cinnamon · Zest and juice of 1 lemon · 2 tablespoons butter · Loaf of white bread (sliced, crusts trimmed) · ¼ cup melted butter, more as needed