2 ½ pounds apples (about 6), preferably Gala or Granny Smith, cored, peeled and sliced into thin wedges

juice of ½ lemon

2 teaspoons cinnamon, divided

2 tablespoons maple syrup, divided

½ cup plus 1 tablespoon flour, divided

½ cup rolled oats

½ cup slivered almonds

3 tablespoons butter, cut into small chunks, plus more for coating the pan

Preheat oven to 400ºF. Coat the inside of a 9- by 13-inch glass baking dish with butter or cooking spray.