This makes TWO galettes. Follow the instructions and then repeat to make the second galette.
Using a mandoline (always, always use the handguard with your mandoline), thinly slice the heirloom tomatoes, potatoes and onion.
In a large skillet, heat the olive oil. Once hot, cook the onion, fresh rosemary (remove leaves from stem), garlic, salt and pepper.
Once onion is translucent, add the potato slices. Cook until potatoes are tender, tossing frequently.
Remove from heat and allow to cool while rolling out pie crust.
Line a large baking sheet or a large pizza pan with parchment. Place 1/2 of the pie crust recipe (one disk of dough) on the sheet, Press to flatten with your hands, then roll out with a rolling pin. It works best to cover with a sheet of plastic wrap when rolling out.
Roll into a large disk, not worrying about the shape being perfect.
With your fingertip, lightly draw a circle on the dough about 3 inches in from the exterior edge. This will help you to know where to place the filling.
Alternate tomatoes and potatoes on the crust.
Top with 1/4 cup Brazil Nut parmesan.
Gently lift the edges of the parchment, allowing the pie crust edge to fall over the filling. Galettes are rustic, so don't worry about it looking perfect.
Optional: You may brush the crust with egg wash. If you would prefer to not use an egg, you can brush lightly with just water, which will help a bit with browning.
On top of the galette, I place a slice of tomato and a slice of potato for a little garnish.
Bake at 350 degrees for 22-25 minutes, until crust is lightly browned.
Repeat to make second galette, which is nice to share with the neighbor who grows yummy tomatoes!