Preheat oven to 200 C. Grease a standard size muffin tin using softened unsalted butter. In a mixing bowl combine the eggs, milk, salt, sugar and whisk until combined. Add the flour and continue to mix until all the lumps have disappeared. If you've got a blender you can use it, but it's not necessary. If there are a few lumps in the mixture, don't worry as these will disappear in the baking. Divide the batter equally into the 12 cups, filling no more than half way. Bake for 25-30 minutes until risen and golden.
While in the oven prepare two bowls, one with the melted butter, the other with sugar and cinnamon. Once out of the oven, dip the popovers first in the melted butter and then in the sugar and cinnamon mixture.
Be warned the popovers sometimes deflate rather spectacularly once you take them out of the oven, which is a bit of a shame. But this does not detract one bit from their popularity. They are absolutely delicious. Marc and I eat these alongside a cup of hot fresh coffee, whilst the little ones have theirs with Daddy's very special hot chocolate. One day, he may share his recipe!