Place puff pastry in a well-oiled pie dish and top with the blue cheese
Heat the olive oil in a sauté pan on medium heat
Add the sliced onions, salt, pepper and thyme, sauté for 3 minutes
Add the sugar and the wine and sauté 2 minutes
Add the balsamic vinegar and sauté 3 minutes
Pour the sauted onion mixture over the blue cheese and fold the edges of the pastry over the blue cheese and onions. Spray the edges of the tart with non-stick spray and sprinkle the parmesan cheese over the top.
Place in the oven and bake for 25 minutes. Let rest for 5 minutes, cut and serve.
Notes
Salt: Some blue cheeses (especially lesser-quality ones) can be quite salty. So go easy on the salt.This is just one of my fall savory tarts. Try Gruyere, goat, or white cheddar cheese. Sautéed plums, fig jam, roasted butternut squash, mushrooms, or Cipollini onions all make great fillings.Puff pastry dough is one option, but it's getting a little pricey these days. Make your own savory pie crust (see my savory heirloom tomato pie recipe) or try bite-sized, pre-made phyllo tartlet shells sold in the freezer section at most grocery stores.