Preheat the oven to 190°C/375°F/gas 5. Grease two 20cm sandwich tins and line the bases with greaseproof paper circles, then dust lightly with flour.
Beat the butter and sugar together until very light and fluffy.
Add the eggs one by one, making sure you beat each one in well before you add the next, then finely grate the orange zest and fold with the flour.
Divide the cake mix between the prepared tins. Spread it out well with a spatula and bake for 20 to 25 minutes, or until golden, risen and an inserted skewer comes out clean.
Allow to cool in the tins, then carefully turn out onto a wire rack to cool completely.
Mix a few drops of rosewater into the jam, but don’t go crazy with it – it’s very strong!
For the crystallized petals, turn the oven right down to 110°C/225°F/gas 1. Whisk the egg white to stiff peaks. Use a pastry brush to coat the rose petals on both sides with a very thin layer of the egg white, then sprinkle over some caster sugar.
Shake off the excess sugar and lay the petals on a baking tray lined with greaseproof paper. Bake for 3 to 4 minutes in the oven, or until the petals are firm to the touch.
For the vanilla cream, split the vanilla pod lengthways and scrape out the seeds, then whip the cream with the vanilla seeds and sugar until you get soft peaks.
Spread the jam and then the vanilla cream over one of the cakes and scatter the raspberries on top. Place the second cake on top.
Dust with icing sugar and decorate with the crystallized rose petals. Serve on a beautiful cake stand to really show off your creation, and enjoy.