I've been lucky in the past two autumns to be able to pick lots and lots of blackberries.  
Their natural accompaniment is apples, as in apple and blackberry pie, apple and blackberry crumble which we could eat for ever.  
However, I've just found another recipe using blackberries*, which look interesting.


BLACKBERRY PUDDING
25g caster sugar
2 tsp ground cinnamon
450g blackberries, washed
8 thin-cut slices of day-old, quality white bread
50g unsalted butter, at room temperature
grated zest of 1 large lemon
300ml milk
142ml pot double cream
2 large eggs, beaten well
25g demerara sugar

1. Preheat the oven to 180C/gas 4.
2. Mix caster sugar with 1 tsp of cinnamon and sprinkle half of this mixture into the base of a deep 1.5 litre ovenproof dish.
3. Speread bread on one side with butter and cut each slice into two triangles, leaving crusts on.
4. Arrange half the bread in overlapping slices over the blckberries and press down to squash the fruit slightly.
5. Add remaining blackberries then sprinkle the rest of the sugar/cinnamon mixture, along with the lemon zest, over the top.
6. Add remaining layer of bread and press down.
7. use a fork to lightly whisk together the milk, cream and beaten eggs, then carefully pour the mixture evenly over the bread.
8. Mix remaining cinnamon with demerara sugar and scatter over the top.
9. Bake for 40 minutes, or until the crust is golden and crisp and the fruit is bubbling.
10. Serve with fresh pouring cream.

this can be made in advance and kept covered in the fridge.  sprinkle demerara topping on just before cooking.  could also use raspberries instead of the blackberries.  could substitute candied peel for the cinnamon.

* many thanks for Waitrose