Method

• 1

  Grease an 18cm flan tin with some of the butter. Put the rest in a bowl and mix with the sugar, lemon juice, mustard seeds and season with salt and pepper. Spread this mixture over the base of the tin.

• 2

  Cut the tomatoes in half horizontally. Arrange them, cut side down on top of the butter to completely cover the base of the tin. Shred the basil leaves and scatter them on top of the tomatoes.

• 3

  Set the oven to 220C/425F/Gas 7. Sift the flour, mustard and cayenne pepper into a mixing bowl. Season with salt and pepper and stir in the mustard seeds, vegetarian Parmesan-style cheese and oil. Mix together with a knife and then rub in with the fingertips until the mixture resembles breadcrumbs. Bind to a soft but firm dough with the milk.

• 4

  Turn the dough onto a floured surface and knead gently until smooth. Roll to a circle about 5mm thick to fit the top of the tin. Lay it on top of the tomatoes and press down lightly, tucking the edge in around the tomatoes.

• 5

  Bake for 15 minutes on the top shelf until the crust is crisp and golden. Loosen the edge with a knife and turn the tart upside down onto a serving plate. Decorate with extra basil leaves and serve straight away.