Preheat oven to 350°. Line an 8" square pan with parchment.
Cut the cold plant butter sticks into halves, then quarters.
Add the plant butter, vanilla, flour, sugar and salt in a blender or food processor. Pulse until crumbly. Set a cup of the crumble mixture aside. Press remaining evenly into lined baking dish.
Bake 18 - 20 minutes. Allow crust to cool.
Spread strawberry preserves over cooled crust. Sprinkle reserved crumble over the top and bake an additional 25 - 30 minutes. The crumble should be lightly golden.
Allow bars to cool. Refrigerate for a few hours to help bars set + firm up.