Preheat oven to 350°F. Line a 9x13 pan with parchment paper. Set aside.
In a large bowl, stir flour, oats, sugar, brown sugar and salt together. Cut in cold butter. Add egg yolk and vanilla. Stir together.
Reserve 2 3/4 cups in freezer. Pour remaining amount into prepared pan. Press firmly to create bottom crust. Pour jam over crust and spread evenly.
Press together small portions of reserved crust to form small clumps. Spread evenly over jam layer. Bake for 45min or until bubbly and golden brown. Cool completely then cut into bars.
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