Rhubarb Crumble/Crisp

1. This recipe is a change from "Grandmaman's Usual Crisp".  No brown sugar in the topping and flour with the fruit.  Fun to mix things up and enjoyed the first rhubarb of the season at the end of May using my new fluted ceramic plate. 
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3. Combine 1 cup flour, 1/3 cup oats, 3/4 cup sugar and a pinch of salt in a bowl.
4. Stir in 6 tablespoons melted butter and 1/2 cup chopped hazelnuts; squeeze into large crumbles and place in the freezer.
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6. Toss 2 pounds chopped rhubarb (7 cups), 1/3 cup sugar, 1/4 cup flour, 1/2 teaspoon vanilla extract, 1/2 teaspoon orange zest and 1/4 teaspoon salt in a 8-by-8-inch glass or ceramic baking dish. Scatter the crumble on top and bake for 45 minutes at 375 degrees.