Preheat the oven to 180C/350F/Gas 4.
For the soufflé, grease and sugar eight ramekins.
Heat the strawberries, sugar, lemon juice and two tablespoons water in a saucepan until simmering. Stir gently and cook until tender. Remove one or two strawberries per person for a garnish and pour over the kirsch.
Blend the rest of the mixture in a blender to a smooth purée. Pass the purée through a fine sieve into a clean saucepan. Mix the cornflour to a paste with two tablespoons of water and add this mixture to the purée. Bring the mixture to the boil, stirring continuously to avoid lumps.
For the crumble topping, mix all of the topping ingredients together in a bowl, then sprinkle onto a baking tray and bake in the oven for 4-5 minutes, or until golden-brown.
For the soufflé, whisk the egg whites in a clean bowl until soft peaks form when the whisk is removed. Slowly whisk in the sugar until the mixture is glossy and stiff peaks form when the whisk is removed.
Beat one-third of the egg whites into the strawberry purée until well combined, then carefully fold in the remaining egg whites.
Half-fill the ramekins with the soufflé mixture, then add the reserved strawberries and fill the ramekins to the top.
Level the tops of the soufflés with a palette knife, place onto a baking tray and bake in the oven for eight minutes. Carefully sprinkle over the crumble topping, then return to the oven for a further 2-3 minutes.
Serve with a quenelle of clotted cream on top.