Method Prep:1hr › Extra time:2hr chilling › Ready in:3hr
First prepare the moulds for the boxes by finding some 2 inch thick medium density foam rubber. Cut into 2 inch cubes enough for one for each box. Wrap in cling film.
Break the chocolate into small pieces and melt gently in a double boiler or by a brief visit to the microwave. When it is nicely liquid hold one of the moulds by the cling film twist and push into the chocolate. Tilt in all directions until the bottom and four sides are covered. Allow to drain slightly then place on a cling film covered surface (I use a large glazed floor tile). Once they are all done place in the fridge. When they have cooled, repeat the process for a slightly more robust box. Replace back in the fridge.
While they are cooling and while the chocolate is still melted take the rose leaves and dip them into the chocolate. Try to cover only one side of each leaf. Place in the fridge to set. When they are hard very carefully peel away the leaf and discard. Store the chocolate leaves in a cool place for use later.
Now that the boxes have hardened for the second time untwist the cling film and gently ease out the foam cube. Now carefully peel the cling film off the inside of the box. Ok that's the tricky stage finished.
Crystalise the rose petals: Whip the egg white until it is a soft foam. Using a soft pastry brush coat each leaf with the egg and then immediately sprinkle well with the caster sugar. Place in a warm place for about an hour by which time they should have gone hard and crunchy.
Whip the cream until it forms firm peaks. Place slices of strawberry into the base of each box. Using a piping bag half fill the box with cream. Add another layer of sliced strawberry and then fill with more cream.
Arange the petals and leaves on the top of the boxes and serve.