If making the crumble with eating apples, the optional tablespoon of sugar is unneccesary.
Heat oven to 400 degrees F.
Peel, core, and slice the apples thin. Toss with a tablespoon of sugar in a 3-cup steel baking dish.
In a food processor blend the flour and remaining sugars together. Cut up the butter and drop down the processor chute while the processor is running. Keep processing until the crumb mixture starts to clump. Sprinkle the crumb mixture over the apples.
Bake in oven for 35 minutes.
Remove from oven and let sit for 5 minutes.
Serve warm with cream to pour over.