Preparation

• Preheat oven to 350°F. Line a muffin pan with 7 paper liners.
• Prepare crumb topping: In a medium bowl, whisk together dry ingredients. In a separate medium bowl, melt butter. Slowly add dry ingredients to melted butter. Use a fork to blend together until only small pieces remain. Transfer crumb topping to a small rimmed baking sheet or large plate. Set aside.
• In a large bowl or stand mixer, cream together butter and granulated sugar until light and fluffy. Add egg, mixing until fully combined, followed by vanilla, lemon zest and lemon juice. Continue mixing. Scrape bowl as needed. Add salt, baking powder and flour, mixing until fully combined. Finally, add sour cream, mixing until no streaks remain.
• Use a large cookie scoop to divide batter between prepared baking cups.
• Generously coat each portion of batter with prepared crumb topping.
• Bake for 18-20 minutes. Cool in pan for 5-10 minutes or until easy to handle. Transfer to a wire rack to cool completely.
• When muffins are cool, prepare glaze. In a small bowl, whisk together powdered sugar and lemon juice. Use a small spoon or whisk to drizzle glaze over cooled muffins.
• Store in an airtight container for up to several days.