Serious Eats - seriouseats.com

Thanks, guys!

Oatmeal Crumble:
2 sticks unsalted butter, softened (1/2# or 224g)
3/4 cup sugar (168g)
1/2 cup brown sugar (112g)
1 2/3 cups all-purpose flour (200g)
1/2 teaspoon salt
300g oatmeal, finely ground* (~1 3/4 cups steel-cut oats or 3-3/4 cups old-fashioned or quick oats)

Cream together butter and sugars until the consistency of wet sand. Add remaining ingredients and mix until mixture is crumbly. Bake at 325F, stirring occasionally, until lightly browned and crunchy, maybe 15 minutes.

*I've made this crumble with all three types of oatmeal, and it comes out more or less the same regardless of the type used. I think you could make the crumble without grinding (which I do in a food processor or spice grinder, depending on the quantity that I'm grinding) the oatmeal to get more of the oatmeal's texture, but I've never tried it.