Continue to whip the mixture for 7 to 8 minutes, or until very thick and glossy. Add the vanilla and whip for another minute. Remove the bowl from the mixer, then fold in the Nutella until mixed, but not blended. Transfer to an airtight container. The spread can be stored at room temperature for 2 weeks.
Nutrition information per 1/4 cup serving: 140 calories; 30 calories from fat (21 percent of total calories); 3.5 g fat (3.5 g saturated; 0 g trans fats); 0 mg cholesterol; 27 g carbohydrate; 1 g fiber; 17 g sugar; 1 g protein; 25 mg sodium.
Recipe adapted from the King Arthur Flour Co.