Heat oven to 350℉/177℃.
Spay an 8-inch square pan with cooking spray. Set aside.
Combine flour, oats, and brown sugar in the bowl of a food processor.
Pulse until combined.
Add butter, a little at a time, pulsing after each addition.
Continue to pulse until the mixture looks like cookie crumbs.
Place ⅔ of mixture in bottom of prepared pan.
Spread evenly and press down firmly.
Bake for 15 to 18 minutes until just starting to brown.
Remove from oven and spread top with jam.
Sprinkle the remaining ⅓ of crust mixture evenly over the top of the raspberry jam.
Return to oven and bake for about 40 minutes, until set and light golden brown.