Preheat your oven to 425°F (220°C). This high temperature is crucial for the popovers to rise properly.
Use your basting brush to generously coat each cup of the popover pan with melted unsalted butter.
In a mixing bowl, whisk together the eggs and milk until well combined. Add flour, sugar, melted butter, cinnamon, vanilla extract, and salt. Whisk until smooth; a few lumps are okay.
Pour the batter into each cup of the prepared popover pan, filling them about 2/3 full.
Bake for 15-20 minutes, or until puffed up and golden brown.
While baking, mix sugar and cinnamon in a small bowl for coating.
Once done, brush the popovers with melted butter and roll them in the cinnamon sugar mixture.
Enjoy warm, best eaten fresh!
