Preheat the oven to 180C/350F/Gas 4. Lightly grease 6 x 10 cm/4 in individual tartlet tins that are 4 cm/1 1/2in deep with butter.
Divide the pastry into six pieces, roll out on a floured surface and use to line the tins.
As this pastry is so short you may find it easier to press it into the tins in an even layer using the tips of your fingers.
Chill for at least 15 minutes to allow the pastry to rest.
Line each pastry base with a circle of non-stick parchment paper that is first crumpled up to make it easier to handle.
Fill with baking beans or dried pulses and bake for about 15 minutes until the pastry cases look ‘set’, but not coloured.
Carefully remove the paper from the pastry bases, then brush the insides with the egg wash to form a seal.
Place in the oven for another 5 minutes or until the bases are firm to the touch and the sides are lightly coloured.
Remove from the oven and leave until cool enough to handle, then carefully take out of the tins and leave to cool completely on a wire rack.
Reduce the oven temperature slightly.
Place the apples and strawberries in a pan with the caster sugar, orange rind and juice.
Bring to a simmer, then cover and cook gently for 5 minutes until the fruits are tender but still holding their shape.
Remove from the heat and leave to cool.
Sift the plain and wholemeal flour into a bowl with the baking powder, then tip the residue from the sieve back into the bowl.
Stir in the muscovado sugar, almonds and oatmeal.
Rub in the butter until the mixture resembles breadcrumbs.
Divide the cooled fruit mixture among the pastry cases and sprinkle the crumble on top.
Arrange on a large baking sheet and bake for another 20-25 minutes until the crumble topping is crisp and golden brown.
To serve, arrange the crumbles on serving plates warm or cold and using two dessert spoons dipped in hot water add a quenelle of crème fraiche to each one.