Preheat the oven to 350° Butter a glass baking pan (8" x 10" or 9" round pan) and arrange the blueberries evenly in pan.
Zest ½ of the lemon over the berries and dust with the 1 tablespoon of sugar.
In a medium mixing bowl add the eggs and whisk lightly. Pour in the milk and cream and continue to whisk until the mixture becomes pale yellow. Continue to whisk as you add sugar and vanilla followed by the flour and pinch of salt. Finally, add the Limoncello and whisk some more until completely combined.
Pour the mixture evenly over the blueberries and place in the center of the oven rack.
Bake about 30-45 minutes or until the edges turns golden or someplace has puffed up lightly.
Remove from the oven and allow the clafoutis to cool for about 10 minutes. Dust lightly with powdered sugar and garnish with lemon zest. You can top it with a few fresh blueberries if you like.