Cut off top of garlic head, place on a square of foil, drizzle with olive oil and season with salt and pepper
Roast garlic at 400 degrees for 1 hour {can be done ahead of time and refrigerated}
Lay zucchini slices out on a paper towel and sprinkle with salt
Let zucchini sit for 15 minutes, letting the salt draw out the moisture, then flip zucchini and salt the other side
Meanwhile caramelize the onion, cooking over medium low heat in a skillet with the butter and olive oil, stirring occasionally until soft and starting to caramelize, about 20-25 minutes
Add shallot and cook for 5 more minutes
Lay dough round on a silpat or parchment lined baking sheet
Squeeze garlic, releasing the roasted garlic from it's papery shell, and spread it all over dough with the back of a spoon or with your fingers
Sprinkle dough with 1/3 of the cheese, leaving a 1 inch border
Top cheese with 1/2 of onion shallot mixture and 1/2 of zucchini
Repeat layers
Fold the border dough up and over filling, making pleats as you go around the edge
Brush folded dough with egg wash
Bake at 400 degrees for 30 minutes for 30 minutes or until golden
Cut into wedges to serve
Serves 4 as a main dish or 6 as a side dish
Notes
do not skip the step of salting the zucchini otherwise you will have a soggy galette!