Divide frozen berries evenly among 4 small bowls.

Sprinkle each bowl with 1/2 teaspoon of granulated sugar and set aside.

Combine polenta and milk in a medium saucepan over medium heat.

Cook for 5 minutes, or until smooth and hot, stirring with a whisk.

Remove polenta mixture from heat.

Stir in 1 1/2 tablespoons granulated sugar, butter, vanilla extract, and salt.

Preheat broiler.

Divide polenta mixture evenly over the fruit in each bowl.

Sprinkle 1 teaspoon of light brown sugar over each bowl.

Place bowls on a baking sheet.

Broil for 1 minute, or until sugar melts and begins to caramelize.

Let stand briefly before serving.