Livres Lust: Tomato upside-down tart

This is a tart that my Mum occasionally puts together in the summer months; it's ideal for a picnic or a buffet. In fact, my relatives often ask her to bring one if they are to host a family gathering.
Any dish with Balsamic vinegar in captivates me from the word go, so it had every chance of success. I can tell you that this was no exception.

The base is made from a concoction consisting of:
Self raising flour 175g,
Butter 75g,
Grated carrot 75g,
Grated cheese 50g,
An egg- beaten,
Salt, pepper, mustard powder, and mixed herbs (parsley, coriander, chives)

Mix together the seasonings with the flour.
Rub the butter in until you have fine breadcrumbs.
Next, stir in the cheese, carrot and herbs.

You should have something looking like this

Add the egg to bind it all together. This will form the base. Use your hands to shape it into a ball, clingfilm and refrigerate.

Meanwhile, preheat the oven to 190C, grease and line a tin, and blanch 550g of tomatoes.

Once blanched, peel off the skin, cut them into thick slices.

Cook off 175g of onions with a little butter. Mix in your sliced tomatoes.
Add some balsamic vinegar and a 1 tbsp of soft brown sugar. Once the tomatoes are coated and infused remove them and pop them into a pan with greaseproof paper.

Try to ensure that the 'bottoms' of the tomatoes (rather than the centre from which you can see the pips) are face up- this will be important for later

Chop up some crusts (25g aprox) and mix them up with your caramelised onion mixture. Once you're happy they're all coated pop them on top of your tomatoes.

Now remember that dough/ batter/pastry we made earlier, well now you just need to pop it on top of your bread and onion mix and you're ready to cook it.

About 25 minutes should do the trick- or until golden.

Now comes the magic: at the moment you have a funny looking doughy and pretty aesthetically unappealing 'tart', but once you've turned it upside down you'll end up with something like this