Preheat oven to 350°.
Place oats in a blender or food processor and process until you get a coarse flour.
Combine butter or margarine, sugar, flour, and oats in a large bowl. Use an electric or stand mixer to mix until it forms a crumbly cookie dough texture.
Grease or line a 9x9 baking pan. Press the ⅔ of the cookie dough base into the bottom of the pan.
Spread the jam over the top of the cookie base.
Drop the remaning dough in clumps over the top of the jam.
Bake the bars for 25-30 minutes at 350°, or until the crumble topping turns golden brown.
Allow the squares to cool for 10-15 minutes before cutting. Enjoy!