French tomato tart with a lot of mustard

I guess you gathered from yesterday's tomato posting that we're swamped with tomatoes this year. That means lots of tomato dishes - like this flavorsome tomato salad, for instance. Here's another flavoursome tomato dish - a mustardy French tomato tart that's excellent with some peppery green salad leaves. Choose tomato variety with few seeds, as then you don't have to deseed or drain them first and save some valuable time for yourself.

French tomato tart
(Sinepine tomatipirukas)
Serves six to eight

Crust:
200 g plain flour
pinch of salt
100 g butter
1 egg

Topping:
3 Tbsp sour cream, creme fraiche or double cream
3 Tbsp Dijon mustard
5 to 6 medium sized tomatoes
sea salt flakes and freshly ground black pepper
fresh thyme or oregano
extra virgin olive oil, to drizzle

First make the tart crust. Mix flour, salt and cold cubed butter in the food processor until crumbly, then add the egg and give it a few turns. Press into a dough ball with your hands, then use your fingers to line a 26 cm pie dish with the dough. Pierce the bottom with a fork in a couple of places, then place into the fridge for half and hour.
Bake the cool crust in a preheated 200 C oven for about 15 minutes (you can also blind-bake, but I didn't bother with that).
Combine mustard and cream, then spread onto the base of the pre-baked pie crust.
Cut the tomatoes, crosswise, into 5 mm slices, layer nicely onto the mustard layer. Season with salt and pepper.
Bake in the pre-heated 200 C oven for about 40 minutes, until tomatoes are nicely roasted and coloured.
Drizzle with some olive oil, sprinkle fresh thyme or oregano leaves on top and serve either hot or cold.