Lightly coat a 9-inch pie plate with vegetable cooking spray. Peel, core, and cut into eighths and arrange them in the pie plate.
Combine 1/2 cup minus 2 tablespoons sugar, flour, eggs, whole milk, vanilla, unsalted butter, and a pinch of salt in a blender. Pulse until smooth, about 30 seconds.
Pour over the pears. Place in the oven and bake until springy to the touch, 25 to 30 minutes. Remove from oven. Heat broiler. Sprinkle the pancake with ground cinnamon and the 2 tablespoons sugar. Broil until browned, about 1 minute. Serve warm.