1. Heat a 10-12 inch skillet over medium heat for 5 minutes. Meanwhile, beat the egg lightly in a shallow pan or pie plate; whisk in the melted butter, then the milk and vanilla, and finally the sugar, flour, cinnamon and salt, continuing to whisk until smooth. Soak the bread without over-saturating, about 30 seconds per side. Pick up the bread and allow the excess batter to drip off; repeat with the remaining slices.

2. Swirl 1 TBSP butter in the hot skillet. Transfer the prepared bread to the skillet in a single layer; cook until golden brown, about 1 min 45 seconds on the first side and 1 minute on the second. Serve the French toast immediately. Continue, adding 1 TBSP butter to the skillet for each new batch.