To make the filling, place cheese, lemon zest, honey and finely chopped walnuts in a medium bowl. Blend with a rubber spatula. Gently fold in blueberries.
Spread one side of four French bread slices with a generous amount of the stuffing mixture. Top this slice with a plain slice of French bread, creating four sandwiches.
To prepare the batter, whisk the eggs into a medium bowl. Add the milk, vanilla and cinnamon and whisk until blended completely.
Place the "sandwiches" in the batter and turn them from side to side. Let them absorb some of the batter on each side.
Melt the 1 Tbsp. butter in a 10-in. nonstick omelette or fry pan on medium-low heat. Swirl the butter to coat the bottom of the pan.
Place the "sandwiches" in the pan and sauté, on each side until they are golden brown. Place on a warm plate.
Top with warmed maple syrup and a sprinkling of fresh blueberries.