In a bowl mix the butter and brown sugar. Then add the flour, the mixture should be a little crumbly. Press into the bottom of an 8x8 inch pan. Bake at 350 degrees for about 12 minutes.
Apple Filling
While the crust is baking. Combine the sliced apples, brown sugar, flour, and nutmeg in a bowl. Toss to combine. Making sure the apples are all coated. Set aside until crust is done
Crumble Topping
In a medium bowl, combine the flour, sugar, and cinnamon. Mix until well combined. Cut in the cold butter to make a crumbly mixture. Set aside until time to assemble.
Once the crust is baked place the coated apples on top and then cover with the crumble topping.
Bake at 350 degrees until the apple mixture is bubbly and the crumble topping is golden.