Preheat the oven to 400ºF (200ºC). Liberally grease a nonstick popover pan, or a muffin pan with 1/2-cup indentations,with softened butter.
For the puffs, put the 2 tablespoons melted butter, eggs, milk, salt and sugar in a blender and blend for a few seconds.
Add the flour and whiz for about 10 seconds, just until smooth.
Divide the batter among the 9 greased molds, filling each 1/2 to 2/3rds full.
Bake for 35 minutes, or until the puffs are deep brown.
Remove from the oven, wait a few minutes until cool enough to handle, then remove the popovers from the pans and set them on a cooling rack. If they’re stubborn, you may need a small knife or spatula to help pry them out.
Mix the sugar and cinnamon in a medium bowl. Thoroughly brush each popover all over with the 1/4 cup (60 g) of melted butter, then dredge each puff generously in the sugar and cinnamon mixture to coat them completely. Let cool on the wire rack.