Using the teaspoon of butter, grease a deep pie dish or pudding basin.
Place the raspberries in a large mixing bowl and sprinkle over the sugar.
Set aside.
Using a teaspoon, sprinkle a little of the milk over each slice of bread to moisten it.
Line the dish or basin with two thirds of the bread slices, overlapping the edges slightly.
Pour the raspberries into the dish or basin and arrange the remaining bread slices on top to cover the raspberries.
Place a sheet of greaseproof or waxed paper on top of the dish or basin and put a plate, which is slightly smaller in diameter than the dish or basin, on top.
Place a heavy weight on the plate and put the pudding in the refrigerator to chill for at least 8 hours or overnight.
Remove the pudding from the refrigerator and lift off the weight and the plate.
Remove and discard the greaseproof or waxed paper.
Invert a serving plate over the top of the dish or basin and, holding the two firmly together, reverse them giving a sharp shake.
The pudding should slide out easily.
In a medium sized serving bowl, using a wire whisk or rotary beater, beat the cream until it is thick but not stiff.