A crisp, buttery pastry crust is folded up around ripe sliced tomatoes. A thin layer of grainy mustard and cheddar cheese adds extra flavor to this simple, beautiful summer dish. —Posie (Harwood) Brien
one 10" tart
For the crust
1 1/2 cups
cheddar cheese powder (optional)
cold unsalted butter (1 stick)
ice cold water
For the filling
grated cheddar cheese (or other flavorful melting cheese, like Gruyere)
Whisk together the flour, salt, and cheese powder (if using). Note: The cheese powder is optional but is a really awesome addition -- use the extra in biscuit dough or over popcorn!
Cut the cold butter into the flour mixture until it is in coarse, uneven pea-sized lumps. Drizzle the ice water over top and stir with a fork until the dough just begins to come together.
Turn the dough out onto a surface and begin to gently knead and press it together, turning it over onto itself and handling it carefully to avoid warming up the butter. If there are too many dry spots, drizzle a tablespoon or two more ice water over top (a spray bottle actually works really well here to evenly disperse the water).
Once the dough comes together, press it gently into a disc. If your kitchen is warm, refrigerate the dough for 30 minutes until warm. Otherwise, go ahead and roll it out right away.
Roll the dough out into roughly a 13" circle. It should be very thin, but if there are any tears, make sure to patch them so the filling doesn't seep out.
Spread the mustard on top of the dough circle, leaving about 1 1/2" inches bare on on the edges. Sprinkle the grated cheese on top of the mustard. Transfer the dough circle to a baking sheet.
Arrange the sliced tomatoes neatly in circles on top of the grated cheese. Fold the edges of the pastry up, pleating as you go to seal the edges. Check to make sure there are no spaces or tears where the filling can seep out.
Drizzle the olive oil over top of the tomatoes, then sprinkle on the flaky salt and herbs.
Bake the galette for about 30 minutes, or until the crust is golden brown and the filling is bubbling.