Preheat your oven to 350°F (175°C).

Arrange cubed white bread evenly in a 9x13-inch baking dish.

In a mixing bowl, blend melted butter, sweetened condensed milk, whole milk (or half and half), sugar, eggs, salt, and cinnamon for 1-2 minutes until smooth.

Pour the custard mixture evenly over the bread cubes, pressing down gently.

Bake uncovered in the preheated oven for about 1 hour until the edges are golden brown and the center is set yet slightly jiggly.

While the pudding bakes, melt butter with condensed milk and brown sugar in a saucepan over medium heat, then stir in vanilla extract.

After baking, poke holes in the pudding and pour half of the warm sauce over it. Let cool for an hour.

Serve warm, drizzled with the remaining brown sugar vanilla sauce.