Preheat the oven to 375 degrees Fahrenheit and spray a 9x9 inch baking dish with cooking spray.
In a large bowl, add the rolled oats, all-purpose flour, brown sugar, and salted butter.
Mix until everything is combined.
Press ⅔ of the mixture into the bottom of the prepared baking dish, spreading it evenly and pressing firmly to the edges.
Drop the strawberry jam on top of the rolled oat mixture and spread it using a spoon.
Lay sliced strawberries on top of jam.
Crumble and drop the remaining ⅓ of the rolled oats mixture all over the top of the strawberry jam.
Bake in the oven for 30-35 minutes or until the top layer is golden brown and the jam is bubbling.
Let cool for at least 30 minutes before carefully cutting into squares and serving.
To Store: Place your bars in an airtight container and store them in the refrigerator. They will last about 4-5 days when chilled.
To Freeze: You can freeze your bars for about 2-3 months in a freezer-safe container. Thaw them overnight in the refrigerator before serving.
Make sure that your bottom layer has a good thickness to it. You want the top layer of rolled oats to be thin, while the bottom layer is thick enough to hold the strawberry jam.
Even though you are crumbling and dropping the top layer of rolled oats, try to spread it as evenly as possible without disturbing the strawberry layer underneath. That way the bars will have a distinct layer to them.
For easier removal, you can put down a layer of parchment paper instead of cooking spray in the baking dish. Then you can just lift your bars right out of the dish.