Preheat oven to 350 degrees F (180°C). Grease a shallow casserole baking dish, around 8×11” or similar size.
Batter: In a large bowl add half and half, butter, vanilla, sugar and salt. Microwave for about 1 minute, just until butter has melted. Add the beaten eggs and cinnamon to the milk mixture then whisk well to combine.
2 cups half and half,2 Tablespoons butter,1 teaspoon vanilla extract,⅓ cup granulated sugar,pinch salt,3 eggs,½ teaspoon ground cinnamon

Add bread to bowl and stir to coat. Pour mixture into prepared pan.
1 loaf day old brioche bread or challah bread
Bake for 30 to 45 minutes, or until custard is set but still a little wobbly and edges of bread have lightly browned.
Serve warm or at room temperature. Drizzle with vanilla cream sauce, if desired.
Vanilla Cream Sauce