1. Preheat the oven to 350°F and grease a 9×13-inch baking dish.

2. In a large bowl, mix the vanilla cake mix, eggs, milk, and vegetable oil until smooth.

3. Pour the batter into the prepared baking dish and spread it evenly.

4. Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean.

5. Let the cake cool for 5 to 10 minutes, then poke holes all over the top using the handle of a wooden spoon.

6. In a bowl, stir together melted butter, brown sugar, and cinnamon until smooth.

7. Whisk in the sweetened condensed milk until the cinnamon filling is creamy and pourable.

8. Slowly pour the filling over the warm cake, spreading it gently so it sinks into the holes.

9. Beat the cream cheese until smooth, then mix in powdered sugar, vanilla extract, and heavy cream until creamy.

10. Spread the glaze over the cake once the top is no longer hot.

11. Chill for at least 1 hour before slicing, or serve slightly warm for a gooier texture.