I have been making this tart for a couple of years now from a recipe I found on the internet. There are many sources of this recipe (and several variations), so I don't know which one to reference as the source. The "original" uses a standard pastry crust, but I prefer puff pastry for ease, and I've changes the amounts slightly for some of the ingredients.
1 portion puff pastry (approx 200 grams)
2 large apples (I used pink lady), peeled, chopped, sprinkled with lemon juice to keep from browning
1/3 cup walnut pieces
1/3 cup blue cheese, crumbled
3/4 Tbsp fresh thyme
2 Tbsp maple syrup
Preheat oven to 450.
Roll out puff pastry to approximately 10"x10" and crimp at edges (this is mainly for looks, the ingredients are not runny at all, so shouldn't spread). Put on a pan lined with parchment paper.
Toss all remaining ingredients together and place on top off pastry. Bake until pastry is puffed and lightly browned - about 20 minutes. If walnuts look like they might burn during cooking, place a small sheet of aluminum foil over the topping, but try to keep the edges visible so they can brown properly.