You can use fresh or frozen blueberries.
Mash the blueberries and sugar with a fork. Add the bread cubes toasted in butter and the liquid cream and mix everything together. Bring to the table in a nice baking dish.
Tip: It is advisable to mix the bread cubes and the cream with the blueberries only before serving. You can also just fold the cream into the berries and sprinkle the bread cubes on top.