Giant strawberry shortcake

The Great British Bake Off winner combines two classic bakes - Victoria sponge and jammy shortbread. The result is dazzling
Ingredients
For the shortbread
400g slightly salted butter, softened
200g golden caster sugar
2 tsp vanilla extract
600g plain flour, plus a little extra for dusting
For the cake
140g slightly salted butter, softened, plus extra for greasing
140g golden caster sugar
3 medium eggs, beaten
1 tsp vanilla extract
140g self-raising flour, plus extra for dusting
For the buttercream
140g slightly salted butter, softened
300g icing sugar, plus extra for dusting
1 tbsp vanilla extract
For the strawberry filling
300g strawberry jam
 ¼ tsp golden linseed
icing sugar, for dusting
Method
Heat oven to 180C/160C fan/gas 4. to make the shortbread, beat the butter, sugar and vanilla extract together until smooth. Add the flour in 2 or 3 goes, and stir until the mixture starts to form a dough. Use your hands to bring it together and shape into a ball. Cut off 100g of the dough, wrap in cling film and chill until ready to make the strawberry stalk and leaves. Weigh the remaining dough and divide into 2 equal pieces.
    Using your hands and the back of a metal spoon, press one of the larger pieces of shortbread mixture into the base of a 23cm loose-bottomed fluted tart tin (wrap the other piece of dough in cling film and chill until needed). Smooth the surface with the back of the spoon to create an even layer, then chill for 15 mins.
    Prick the base of the shortbread all over with a fork, place on a baking tray and bake for 20-25 mins or until lightly golden and firm. Remove from the oven and, while the shortbread is still hot, press a 9-10cm heart-shaped cutter into the centre. Leave to cool in the tin for 20 mins.
    Carefully remove the shortbread from the tart tin and transfer to a wire rack to cool completely. Wash the tin and repeat steps 2 and 3 with the second piece of dough, but don’t cut out the heart shape. (If you have 2 tart tins you can make both the shortbread biscuits at the same time.)
    For the cake, grease the base and sides of a 22cm springform cake tin and line the base with baking parchment. In a large bowl, beat the butter and sugar together until light and fluffy. Add the eggs and vanilla a little at a time, beating well after each addition, then fold in the flour. Spoon the mixture into the prepared tin and smooth the surface. Bake for 20-25 mins until lightly golden and a skewer inserted into the centre comes out clean. Leave to cool for 10 mins, then remove from the tin and transfer to a wire rack to cool completely.
    Meanwhile, cut out the strawberry stalk and leaves. Roll out the 100g piece of reserved shortbread dough on a lightly floured surface to the thickness of a £1 coin. Using a leaf cutter or a knife, cut out 4-5 leaf shapes, then cut out a 4cm-long strawberry stalk. It is best to do several so you can choose the best ones. Lift the shapes onto a baking tray lined with baking parchment and chill for 15 mins. While the cake is cooling, bake the leaves and stalks for 5-10 mins until lightly golden. Leave to cool on the tray for a few mins before transferring to a wire rack to cool completely.
    To make the buttercream, beat the butter in a large bowl until soft and pale. Sift over half the icing sugar and beat until combined. Sift over the remaining icing sugar, add the vanilla extract, then beat until smooth and creamy. Transfer to a disposable piping bag fitted with a wide round nozzle, or simply snip off the end of the bag.
    Start assembling the shortcake. Place the shortbread biscuit without the heart cut-out on a plate or cake stand, pricked-side up. Starting in the centre, pipe on the buttercream in a spiral, working your way towards the edge. Lay the cake on top of the buttercream, then spoon the jam on top of the cake and carefully spread out over the surface.
    Remove the heart from the second shortbread biscuit and set aside. Carefully flip the biscuit over so that it is pricked-side down and, using a cake paddle, slide it on top of the jam layer. Dab a little buttercream or jam on the back of the stalk and leaf biscuits, and stick to the edge of the strawberry jam heart.
    Carefully place individual linseeds inside the jam heart to create the appearance of a strawberry. Dust the surface of the shortcake with icing sugar, holding the reserved heart biscuit over the jam and leaves so that they do not get covered in icing sugar.
Source: Good Food