Preheat oven to 375F. Lightly grease an 8 inch, cast iron skillet or similar sized baking dish with some butter.
Put the eggs and sugar in a bowl or mixer and whisk well until well broken up and combined. Add the milk, flour, vanilla, lemon zest and salt and mix/whisk until smooth.
Cut the pears in half and remove the core. Cut into slices and arrange in the bottom of the skillet/baking dish – you can fan them out slightly or arrange any other way you choose.
Carefully pour the batter into the skillet/baking dish over the pears.
Bake in the oven for roughly 35 minutes, until lightly browned around the edges and set.
Remove from the oven and allow to cool for a couple of minutes before serving. It will probably be puffed up when you take it out the oven and collapse slightly after a minute.
Sprinkle with a little confectioner’s sugar to serve, if desired.