Place both flours into a mixing bowl. Cut 125g of the butter into small cubes and rub into the butter until well combined.
Beat the lemon juice, egg yolk and water. Add this to the flour; lightly knead to form a dough.
Add a little more water if needed but it should be firm.
Wrap well in cling film and chill for 30mins.
Roll the pastry out on a well floured surface to about 50cm x 30cm.
Slice the remaining butter and lay it over 2/3 of the dough. Fold the unbuttered 1/3 over 1/2 the buttered area. Then flip that over the remaining butter third so the butter is wrapped inside the dough.
Using a rolling pin lightly roll the upper surface of the dough to press out any air bubbles.
Press the edges to seal. Wrap in cling film and chill for another 30 mins.
On a lightly floured surface roll the dough out until it measures 60cm x 20cm. Fold the pastry in by 1/3s until it is a 20cm x 20cm parcel. This is called giving the dough a single turn.
Place on a plate and chill for 30 mins. To give the dough its second turn roll the dough in the direction of the unfolded sides to form a 60cm x 20 cm rectangle. Fold in by 1/3s to give a 20cm x 20cm parcel again. Chill once more for 30 mins.
Repeat this twice more each time rolling in the direction of the unfolded side and chill in for 30 mins in between.
Then cover and chill for 1 hour. When ready to use roll into the desired shape on a tray.
Chill for 30 minutes before baking.
For the tart: Lightly brush a 30cm x 25cm tin with oil. Roll the pastry out to shape the tin, Cut a 1cm strip from each side and using egg wash 'glue' this around the edges to form a border. Cover and Chill for 30 mins.
Preheat the oven to 180C. Spread the pesto onto the pastry base. Arrange the slices of tomato and goats cheese on top.
Season with salt, pepper and drizzle with oil, brush the edges with egg wash.
Bake for 15-20 mins until puffed up and golden.
Garnish with basil leaves and serve with a green salad.