Line a 20x30 cm (8x12in) baking pan with baking paper.
Put the sugar, flour, baking powder, salt, egg and butter in an electric mixer and mix until just combined.
Press the mixture into the base of the prepared pan and bake it in a pre heated oven at 180°C – 350°F for 20 to 25 minutes or until golden and firm. Let it cool completely.
Put the strawberries, sugar and vanilla in a bowl and toss to combine. Keep aside.
Put the flour, butter and sugar in an electric mixer and mix until just combined (it will look like coarse breadcrumbs).
Using a slotted spoon and shaking off the excess juice, distribute the strawberries over the cooked base. Top them with the crumble topping and bake it in a pre heated oven at 180°C – 350°F for 35 to 40 minutes or until golden.
You can use any excess strawberry juices over some yogurt or vanilla ice cream.