Authentic Spanish Crema Catalana Recipe

Name: Authentic Spanish Crema Catalana Recipe
Prep time: 15 min
Cook time: 10 min
Total time: 25 min
Cuisine: Spanish
Ingredients: 2 tablespoons cornstarch; 2 1/2 cups whole milk; 1 large piece lemon peel (including pith); 1 large piece orange peel (including pith); 1 cinnamon stick; 5 large egg yolks; 1/2 cup white sugar (preferably caster (superfine)); additional sugar (for caramelization); fresh fruit or berries (for decoration (optional))