Preheat oven to 375° and set a rack to the upper third of the oven. Unwrap the puff pastry and lay on a lightly floured cutting board. Cut the sheet into 16 squares, then halve those squares diagonally to make 32 triangles. Arrange each triangle about 1/2 inch apart on a baking sheet.
Sprinkle equal portions of pear in the center of each triangle, then top with equal parts Gorgonzola and walnuts. Bake until puffed and golden, 15 to 20 minutes. Sprinkle all over with thyme and serve warm.