First, prepare the crumble. Use your hands to incorporate butter into flour. Texture will remain chunky. Add sugar, spices, oats, rosemary, and orange zest. Set aside to chill in refridgerator for 30 minutes.
Next, prepare your apples. Place a large skillet over low heat. Toss apple slices with bourbon and add to the pan, cooking for about 10 minutes, or until the apples have softened and the bourbon has reduced.
Layer apples in an approximately 8x8 baking dish. Sprinkle on crumble mixture and bake for 30 minutes, or until bubbling.