chocolate chip sour cream coffee cake

INGREDIENTS

• 1/2 cup unsalted butter (1 stick, 4 ounces or 113 grams) at room temperature
• 1 1/2 cups (300 grams) granulated sugar
• 3 large eggs, separated
• 1 1/2 teaspoons vanilla extract
• 2 cups (16 ounces) sour cream
• 3 cups (375 grams) all-purpose flour
• 1 teaspoon baking powder
• 1 1/2 teaspoons baking soda
• 3/4 teaspoon table salt
• 2 cups or 12 ounces semi- or bittersweet chocolate chips or coarsely chopped chocolate bars
• 1/2 cup (100 grams) granulated sugar
• 1 teaspoon cinnamon