Preheat oven to 350 degrees F and prepare a 8x8 inch square baking pan with parchment paper

In a mixing bowl with paddle attachment, cream together the butter, light brown sugar and vanilla extract until fully combined

On low speed, slowly add the flour and salt to the butter mixture until it becomes a crumbly texture

Add ¾ of the shortbread dough to the prepared pan and press down to create a flat and even surface

Spread the jam on top of the shortbread base and then add the remaining crumble to the top of the jam

Bake for 25-30 minutes or until the shortbread turns a light golden color

Remove the Jam Shortbread Bars from the oven and allow them to cool completely before removing them from the pan (refrigerate if you are in a rush) 

Once the bars are cool, remove them from the pan and cut them into the desired shape and size

Serve or store in an airtight container for 4-5 days