In a large saucepan, add the fruit (reserving a few berries for garnish). Add the sugar and cook until the fruit is starting to release some liquid, is tender and beginning to burst, but still holds its shape, about 5 minutes.
Line a large 6-cup pudding bowl with plastic wrap, allowing lots of overhang.
Remove the crusts from 10 to 12 slices of bread. Press the bread slices briefly in the juices at the top of the berries in the pot then lay them into the bowl, juice-side down, ensuring there are no spaces. Use smaller pieces to overlap or close gaps in spaces, as needed.
Remove the berries from the heat, and cool slightly. Using a slotted spoon, spoon the fruit into the bread-lined bowl, and top with a final layer of bread and spoon a bit more of the juices over the top to color the top layer of bread evenly. Reserve the remaining cooking juices for serving. Cover with the plastic wrap and place a plate over the top. Add a large heavy can or a 2-pound weight to the plate and let sit at least 8 hours, or overnight, refrigerated.
On serving, whip the cream until soft peaks just begin to form. Add the sugar and whip until almost stiff.
Gently invert the bowl onto a large serving dish, shaking it lightly to loosen. Peel the plastic wrap off, and spoon the reserved juice all over, to soak any bits of bread that still look white. Serve with a bowl of whipped cream on the side, or cut individual wedges, and add a dollop of cream and a berry or two for garnish.