Preheat oven to 180°C. Line an 8×8 pan with greaseproof paper
In a medium bowl, combine, flour, oats, salt and baking powder.
In a large bowl, whisk butter, brown sugar and vanilla until well combined. Add dry ingredients and stir with a wooden spoon until combined.
Set aside a little less than half of the dough. Turn the remaining dough into the prepared pan and press it down into a flat even layer. Bake for 10 minutes.
Remove from the oven and carefully spread the jam on top of the base. Take the reserved dough and crumble it over the top of the jam layer. Return to the oven and bake for 14-16 more minutes, until the topping is light golden brown. Place the pan on a wire rack to cool.
These bars are soft when they are warm (they likely won’t hold together). To firm them up they can be stored at cool temp or refrigerated.