Lightly grease an ovenproof dish and add the blueberries.
Melt the butter and leave to cool.
Mix the eggs, sugar, vanilla, orange rind and juice, and flour in to a bowl and whisk by hand until smooth.
Gently mix in the soured cream and melted butter.
Pour over the berries and put it straight in the oven for 35-40 minutes until it starts to go golden brown.
Serve straight away – watch out as the blueberries will be very hot.