To make things simple, we have used frozen mixed berries in our summer pudding, but if the availability is good, just replace with a selection of your favourite fresh berries.
Place the mixed berries in a large pan with the caster sugar and 3 tablespoons of water.
On a low heat, gently warm for 5 mins, until the juice from the fruit starts to seep out.
Drain the juice from the fruit through a sieve set over a large bowl.
Line a 1.2-litre pudding basin with a double layer of cling wrap, leaving an overlap around the top.
Cut one slice of bread in half widthways and trim the corners to fit into the base of the bowl – you may need to use both squares, trimmed to fit.
Trim the slices to the correct length to line the sides of the bowl.
To assemble the pudding, dip the slices of bread into the fruit juice, use them to line the basin.
Start with the bottom pieces, then lay soaked rectangles of bread around the sides of the bowl.
If you have any gaps left at the end, patch these up with any remaining bread, but make sure you save some for the top (which will become the base).
Tip the fruit into the lined basin.
Finish the pudding with a layer of bread to make a base, then pour over any remaining liquid.
Wrap the overhanging cling film over the top.
Place a small plate, which will fit snugly on top of the basin, over the cling film and weigh down with 2x 400-gram cans of tomatoes or beans.
Leave the pudding weighed down in the fridge for at least a couple of hours, or overnight if possible.
When ready to serve, unwrap the cling film and place a serving plate over the pudding. Flip it over and remove the basin. Carefully peel away the cling film.
Serve in slices with the custard poured over the top.
2x 500-gram packs Windermere Berry Farm mixed berries, defrosted
100 grams Essente caster sugar
400 grams Farro white sliced loaf, crusts removed
500 grams Dollop vanilla bean custard