Prosciutto and Cheese Tartine

I made this for guests as part of an Italian themed dinner - it was a huge hit!! I used 1 puff pastry sheet instead of making the dough. I added shredded fontina cheese, the walnuts, onion and thyme then baked for about 10 minutes. I let it sit until I was ready to serve. I also let the arugula sit on paper towels after I tossed it with the oil and juice so it would be too 'soggy'. So easy and partially make ahead.

I made this as written and it was wonderful, full of flavor and texture.