Coffeecake Muffins

INGREDIENTS

• ½ cup pecans
• ¼ cup (1¾ ounces) dark brown sugar
• 1 teaspoon ground cinnamon
• 2 cups (10 ounces) all-purpose flour
• 1 cup (7 ounces) granulated sugar
• 1 teaspoon salt
• 8 tablespoons (1 stick) unsalted butter, cut into ½-inch pieces and softened
• 1½ teaspoons baking powder
• ½ teaspoon baking soda
• ¾ cup sour cream
• 1 large egg
• 1 teaspoon vanilla extract
• :
• 1 cup confectioner's sugar
• 2 tablespoons water