Rhubarb Coffee Cake with Crumbly Topping

Ingredients

• 3/4 cup butter, softened
• 1-1/2 cups sugar
• 3 large eggs
• 1-1/2 teaspoons vanilla extract
• 3 cups all-purpose flour
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 3/4 teaspoon salt
• 1 cup sour cream
• 3 cups chopped fresh or frozen rhubarb
• TOPPING:
• 1/2 cup packed brown sugar
• 1/4 cup all-purpose flour
• 1 teaspoon ground cinnamon
• 1/4 cup cold butter