Pre-heat oven 356°F/180°C/160°C fan. Line a 9 or 10-inch square baking dish with parchment paper.
Jammy filling: Add all the ingredients into a saucepan, and heat over low-medium heat. Once the sugars melted and the mixture starts to bubble, cook for a further 2-3 minutes or until it thickens up a little more. Set the jammy strawberry filling aside.
Soft buttery crumble: Combine AP flour, light brown sugar, oats and salt. Next, add the salted vegan butter and mix until it resembles crumbs. Add 3/4 of the crumble mixture into the pre-lined baking dish. TIghtly press the mixture into the pan to form the base with clean hands or the back of a measuring cup. Bake for 6-8 minutes.
Bake together: Pour the strawberry filling over the base, and crumble over the remaining topping. Bake for 45-60 minutes or until the top becomes a little golden.
Rest: Allow bars to rest for 2 hours, and then pop them into the fridge to cool for a further hour or two. Slice into 16 bars using a serrated knife, and enjoy!