Make the pastry. Place the flour, salt, and cold butter into the food processor and pulse till butter is in small pea sized pieces. Dribble in the ice cold water - and pulse till the mixture just comes together.
Dump pastry dough onto the counter and press it together into a pile, if you've made a double cut into two half piles. Flatten the pastry - smoosh it together - into a (round!) disk and then wrap in plastic wrap and place in the fridge at least one hour - can do a day or two ahead if needed. Note - probably would save you time rolling it out later if you spent a bit of effort making the disk as round as possible before putting into the fridge. Re-seeing these pics, makes me understand how my crostata got so wonky when I rolled it out! #KeepingItReal
Trim off the dark green part and root end of the leeks. Set aside the dark green parts for a different recipe or compost.
Clean the leeks carefully ! Leeks are notorious for having a LOT of dirt inside them based on how they grow. Leeks capture dirt inside their layers as they push up and out of the ground. Looking at this picture of a leek - see how the leek center looks with an oblong growth pattern. Cut down the middle - along the long side of the oblong growth when cutting the leek in half lengthwise. Using this picture as a guide - it's basically cutting right to left. Cutting this way will make the washing of each of the layers easier. You can basically peel back each layer under running water and ensure you don't have any sand or dirt still imbedded in your leek. Finally, chop the leeks into half moons. Alternately, you could chop the leek (dirt and all) and then carefully rinse / wash in a colander letting all the dirt fall to the bottom and spin dry. Set the oven to bake at 450 degrees
Saute the leeks in the butter with the thyme. Add S&P. Ina says to cook about 8 minutes over medium high - till the leeks are tender and beginning to brown.
While leeks are cooking, slice the tomatoes into 3/8 inch slices. Ina says to use only the beautiful inner pieces. I say, who are you feeding (e.g. how fancy do you need to be?) and can you hide the less beautiful pieces on the bottom? Salt and Pepper the tomatoes and drizzle a little EVOO and set aside.
Roll out the pastry to a 11 inch circle. I love to use my handy dandy silicone pastry roller template which was a game changer for me! (I really have no excuse for things not to be round anymore!)
Place rolled out pastry onto parchment and get out your sheet pan. Ina says to invert your jelly roll pan - and cook on the backside. (That sounded a bit too risky for clumsy ol' me....) Alternately if you have a real cookie sheet (no jelly roll sides) then that would work too. Or if you are clumsy like me, you can cook on the jelly roll pan as normal.
Build the crostata: Spread leeks on the bottom of the pastry - leaving 1.5 inch border. Crumble goat cheese over the leeks. Place the tomatoes over the cheese - and Ina says - overlap slightly as tomatoes will shrink when cooked. (That's a GREAT tip!) Flip the edges over the top and crimp a bit. Use the egg wash to brush the pastry edges. Bake for 25 - 30 min until the crostata is nice and brown and smells like you can't wait another minute to eat it.... ha. But you must - allow it to cool 5 minutes minimally and let it set. Sprinkle on the fresh herbs you chopped (basil and chives) and a little large flake salt if you have any.
Serve to your friends and family while warm, if you can.