Preheat oven to 300°F. Spread bread cubes evenly in a shallow baking pan. Bake 20 minutes or until crisp, stirring once. Let cool. Increase oven temperature to 350°F.

Butter six 3- to 3 1/2-inch muffin cups or twelve 2 1/2-inch muffin cups. Fill each cup with toasted bread.

In a large bowl whisk together buttermilk, melted butter, 1/3 cup brown sugar, the eggs, 2 tsp. vanilla, and 1/4 tsp. kosher salt. Slowly pour mixture over bread in each cup. Cover and let stand 30 minutes or chill up to 4 hours.

For maple caramel: Meanwhile, in a small saucepan combine maple syrup and remaining 2 Tbsp. brown sugar. Bring to boiling; reduce heat. Boil gently 2 minutes, stirring occasionally. Remove from heat; carefully add cream, the remaining 1/4 tsp. vanilla, and an additional 1/2 tsp. kosher salt. Return to heat; boil gently 1 minute more, stirring constantly. Remove from heat. Maple caramel will thicken as it cools. (Rewarm, if necessary, for drizzling.)

Bake muffins 30 to 35 minutes or until puffed, golden brown, and set. Let cool 10 minutes. Remove muffins from cups. Serve warm drizzled with maple caramel. Makes 6.