Peel the garlic by breaking the cloves away and placing them into a heatproof bowl. Submerge in boiling hot water for 5 minutes and drain. The skin will become loose and easy to peel away.
Place the garlic cloves and thyme into an ovenproof dish and fully submerge in olive oil. It's important the garlic is fully submerged in the olive oil so it does not burn. Bake for 2 hours or until the garlic has browned in colour.
Allow to slightly cool and store in an airtight container or jar for up to several weeks in the fridge.
Garlic confit & sour cream puff pastry
Chill a large bowl, grater and the butter in the freezer for 20 minutes before making your pastry. Combine the flour and salt into the chilled bowl and mix together with a fork. Grate the butter on the chilled grater and add to the flour. Break the butter into the flour with your fingertips until you have a pebble like crumbly texture. You can do this by pinching and rubbing the butter and flour between your fingers.
Create a well in the centre of the flour and add in the sour cream and garlic confit cloves. Use a fork to combine the flour, sour cream and garlic confit until most of the flour is moist.
Lightly dust your kitchen bench or working surface with flour and mould your dough into a rough disc shape. The dough should be firm and moist but not sticky. You want just enough moisture so the dough is barely sticking to itself. If it needs more moisture slightly wet your hands when working with it or if it’s too dry, lightly dust it with flour. Using a rolling pin, roll the dough out into a thick rectangle shape. Cut the rectangle into thirds and stack each piece of dough on top of each other. Roll them into each other with the rolling pin. Repeat this step two times until the dough is smooth.
Divide the dough into two and wrap each piece in glad wrap. You will only need half of the dough for this recipe. The dough will keep in the fridge for 2 days and in the freezer for 3 months. Leave the dough to rest for a minimum of 1 hour or ideally overnight.
Tomato filling & galette assembly
Preheat the oven to 200 degrees Celsius fan forced / 180 degrees Celsius conventional.
Slice the tomatoes. If they are juicy and have a lot of liquid, place them onto absorbent paper and salt them. Leave to sit for 10 minutes to remove the excess moisture.
Take one disc of puff pastry dough out of the fridge. Sprinkle your kitchen bench or working surface with flour and using a rolling pin, roll the dough out to a large circle shape that is roughly 4mm thick. Roll the dough onto the rolling pin and then place it onto a pre-lined baking tray.
Leaving a 4cm boarder around the edge of the dough, spread the garlic confit cloves onto the bottom of the dough. In a circular pattern, place the sliced pieces of mozzarella on top of the garlic confit, followed by the basil leaves and lastly the slices of tomato. Season with salt, pepper and olive oil. Fold in the overhanging pastry, pinching the dough together to form a rustic circle shape.
Whisk the egg and brush all parts of the dough with it. This will help create a lovely golden colour while your galette bakes.
Bake the tart for 30 - 40 minutes or until the cheese is bubbling and the puff pastry is golden and crunchy. Leave to rest for 15 minutes before cutting into it as this will allow the filling to set. Finish off with a sprinkling of basil leaves and drizzle of balsamic glaze.