Mix all the ingredients together until the mixture resembles breadcrumbs or biscuit crumbs.
Spread the crumble mixture over a baking tray lined with baking parchment.
Bake at 180C/350F for 10-15 minutes until golden. Turn once or twice in this time so the crumbs brown all over and cook until crispy.
Remove from the oven.
Lemon custard (curd)
While the crumble is baking, whisk together the egg yolks, whole egg, sweetener and lemon juice/zest in a saucepan.
Heat over a very gentle heat (whisking continuously) until it is a smooth custard consistency.
Add the butter and mix again while melting. Stir until thickened again.
Remove from the heat.
Whisk the egg whites and sweetener until stiff peaks form.
Place 6 circles of meringue on a baking tray lined with baking parchment.
Bake at 180C/350F for 10 - 15 minutes, or until golden.
Divide the crumble mixture between the 6 glasses or mason jars.
Divide the lemon custard/curd on each of the bases.
Place a baked meringue on top of each to complete the sugar-free & low-carb lemon meringue pies.
Serve immediately or chill in the fridge until ready to serve.
To serve hot, make the crumble base and lemon curd as shown. Layer the base and the curd in individual heatproof jars and cook the meringue directly on top of the sugar-free lemon meringue pie.To serve cold, prepare the 3 layers as shown then construct the sugar-free lemon meringue pies and keep covered in the fridge until ready to serve. This way they can be made a day ahead.