This can also be made with sliced peaches instead of apples, so use whichever fruit is in season. –Sycamore Inn, Arlington, Vermont
In medium saucepan, melt butter, then add oats, brown sugar, and nuts. Mix well. Peel, core, and slice apples and place in greased 13x9-inch baking pan. Cover with oat mixture. Pat down gently. Cover with foil and bake at 375 degrees F for 25 minutes. Remove foil and bake 20 more minutes or until apples are bubbling vigorously. Serve warm with a little heavy cream poured over.