Grease bottom and sides of 9 x 9 inch pan with butter, and preheat oven to 350 degrees F.

In medium-size mixing bowl, combine flour, brown sugar, oats, baking soda, baking powder, salt, and cold butter cubes. Cut together until resembling coarse meal. Add pecans, if desired.

In a large mixing bowl, stir together apple slices, sugar, cinnamon, and melted butter. Spread apples evenly in prepared baking dish. Top with flour mixture, and pat to smooth.

Bake at 350 degrees for 35-40 minutes. It should be golden and bubbly.

Cool slightly on wire rack, and serve warm or cold, plain or with vanilla ice cream or whipped cream. It’s delicious in all its varieties!