To make the bean puree heat a large saute pan over a low to medium flame. Add 2 tbsps oil then the chopped garlic and shallots. Fry for 4-5 minutes until softened and lightly coloured.
Increase the heat slightly and stir in the beans, parsley, marigold bouillion and boiling water. Season and cook for 2-3 minutes stirring vigorously. As soon as it is piping hot scrape everything into a food processor and whisk for 1-2 minutes until reduced to a smoothish puree. Check seasoning and keep warm.
In the meantime season the cod fillets with salt and pepper, then dust them with a little plain flour and lightly oil them.
Heat the frying pan over a very high flame. Pour in 2 tbsps olive oil and wait until it is very hot. Put in the cod fillets and cook for about 2 minutes , then turn over and cook for a further 3-4 minutes until the flakes of fish are opaque and the outside is golden black.
Divide the hot bean puree between 4 warmed plates and put the cod on top. Sprinkle on a little lemon juice before eating immediately.