Roast beetroot soup with beet top pesto

1kg of beetroots with tops, scrubbed, tops left aside

4 cloves of garlic 

Small handful of thyme sprigs

Rapeseed oil

1 litre of vegetable stock

Sea salt and black pepper

Crème fraîche to serve

For the pesto:

Reserved beet tops, leaves only

Small handful of parsley, chopped

1 fat clove of garlic, chopped

Juice of 1 lemon

Pinch of sea salt

50g walnuts

Rapeseed oil