Cut the bread the day before and let them dry in the open overnight.
1. Preheat your convection oven to 180 °C. Remove the crust from the bread and cut the slices into strips about as wide as the thickness of the bread. Spread the strips out on a baking sheet lined with baking paper and dry in the hot oven for about 15 minutes (see tip).
2. In the meantime, mix the sugar and cinnamon in a deep plate. Whisk together the eggs and milk and pour into a second deep plate. Run a knife along the length of the vanilla bean to open it and scrape out the seeds. Stir the vanilla into the yogurt and season with maple syrup to taste.
3. Heat a non-stick pan and cook the blueberries over medium heat for 4–5 minutes, pressing them lightly with a fork. Wash the mint, shake dry, pluck off the leaves and cut into fine strips. Add the mint to the blueberries. Remove the strips of toast from the oven and allow to cool for 15 minutes.
4. Heat 1 tbsp of butter in a second pan. Dip the strips into the egg and milk quickly and then cook until golden brown in the heated butter. Remove the strips from the pan and immediately roll them in the cinnamon and sugar and place on the baking sheet.
5. Place a portion of the French toast strips on a plate with a spoon of blueberries and serve garnished with a dollop of the vanilla mayonnaise.