Heat 2 tablespoons butter in a saucepan.
Stir in 2 tablespoons flour, 1/2 teaspoon salt, and 1/4 teaspoon black pepper; heat until mixture bubbles, stirring constantly.
Remove from heat and slowly add 1 1/2 cups heavy cream and 1 tablespoon tomato paste, stirring until well blended.
Continue to stir, bring to boiling, and boil 1 to 2 minutes.
Mix in 4 teaspoons capers.