In a medium bowl combine brown sugar, oatmeal, flour and cinnamon. Cut in the butter until only small pieces remain. Set aside.
For the filling:
Peel and slice the apples and pears into 1/4 inch slices. Toss gently with lemon juice to prevent browning.
In a medium bowl, combine the remaining flour, cinnamon, nutmeg, brown sugar and vanilla. Add to the sliced apples and pears, tossing gently to coat.
Transfer to a buttered 8×8 inch square baking dish. Bake for 45 minutes or until the fruit is tender and the topping is crisp.
Notes
For the filling, I substituted 2 tsp. apple pie spice from Penzeys in place of the cinnamon and nutmeg. I like the touch of clove spices the apple pie spices add. Additionally, the original recipe only called for 2 Tbsp. flour to be added to the filling. I added three instead, as our pears and apples were particularly juicy. I switched the recipe to use equal amounts of sliced pears and apples.Adapted from Baked By Rachel.