Peel, core, and quarter the pears, then cut into thin slices. Set aside.
In a large bowl, whisk together eggs, sugar, vanilla extract, milk, lemon zest, salt, and flour until smooth. Pour mixture into a greased round, shallow baking dish, then top evenly with pears and blueberries. Bake in the oven until golden brown and set, about 25-30 minutes.
Remove from the oven, let cool for a few minutes, then dust with icing sugar. Serve topped with scoops of vanilla ice cream.