If using redcurrants remove the stalks or do the same for the strawberries. Wash the fruits in cold water, removing any tainted berries.
Put the berries into a large saucepan with the sugar and vanilla bean and place over a medium heat for about 3-4 minutes to allow the sugar to dissolve and the juices to run a little from the berries. Remove the pan from the heat. It’s important at this stage that we don’t cook it too much or the berries will become mush.
Line a large bowl (or a few smaller ones) with cling film and then lay the sliced bread around the sides overlapping a little, press the bread into the sides of the bowl with your hands so you really make a seal.
Once the mould is lined with bread spoon the cooling berries and their liquor into the bowl reserving about 1/2 a cup for spooning over the top. Cover the base of the pudding with another piece of bread, cover with cling film and rest a plate that fits directly on the bread (inside the bowl) and place a weight on top to compress the puddings. Place in the fridge for about twenty-four hours.
Just before serving the pudding turn it out onto a plate and spoon the reserved liquor and berries over the top. Serve with a big dollop of crème fraiche.