Lemon Glazed Shortbread Bars

Ingredients

• 3 cups all-purpose flour
• 1/3 cup corn starch
• 1 1/4 cups powdered sugar
• 1/4 cup lemon zest (5-6 lemons)
• 1 1/2 cups butter, at room temperature
• 1 tbsp. lemon juice
• 1/2 tsp. salt
• 1/2 tsp. vanilla
• 2 1/2 cups powdered sugar
• 2 tsp. lemon zest
• 3 tbsp. lemon juice
• 1 tbsp. light corn syrup
• water, as needed