Preheat oven to 425° with a rack set on bottom. Lay dough flat on a rimmed baking sheet lined with parchment paper. Poke holes all over dough with a fork, leaving the outer inch untouched. Bake until dough starts to puff, about 10 minutes.
Whisk together egg and cheese until smooth and spread over dough, using a spoon to move mixture toward the corners. Sauté onion in oil in a frying pan until softened. Scatter onion and pear over cheese.
Bake until pastry is golden brown and egg has set, about 15 minutes. Sprinkle with thyme and cut into squares.
Note: Nutritional analysis is per 2-piece serving.