Slice strawberries into quarters. And combine with other berries in a large saucepan.
Add sugar, lemon juice, and mint to berries and mix. Set aside half a cup of berry mixture in a small bowl and refrigerate. These will be used as your fancy garnish.
Place the saucepan over medium/high heat until the berry mixture boils. Lower heat, and allow the berries to simmer for approximately 10 minutes or until the berries are very soft and have released their juices. (You should essentially have a berry soup…). Allow the mixture to cool while you prepare the bread.
Slice your chosen bread into ¾-1 inch slices. Lightly butter one side of each slice.
You can make your pudding in pretty much any “vessel” you wish (read: whatever you have lying around in your kitchen). I have used cake pans, glass pie dishes, and a roasting pan...and they have all been awesome. If you have all of these things (impressive!), I have to say that a non-stick 9-inch cake pan may be your best option. Pour about a cup of berry juice into the bottom of the pan, avoiding whole berries.
Overlap the slices of bread, butter-side down to create the first layer of your pudding. Press the bread down firmly (really squish) so that it begins to soak up the berry juice. Pour half of the remaining berry mixture over the first layer of bread.
Repeat the process of overlapping bread, butter-side down to create your second layer. Pour the remaining berry mixture over the pudding.
Cover the pudding tightly with plastic wrap. If your pudding is slightly higher than the vessel it is in, place a weight on top (anything will do: a book, another pot, etc), which will help to compress the pudding and saturate it with those delicious juices. Refrigerate for at least an hour.
To serve: Invert the pudding onto a large plate. (If it doesn’t come straight out, don’t panic! Run a butter knife around the edges). Top with reserved berries and a sprig of mint. This is delicious with vanilla ice cream or lemon sorbet…