Zucchini Nut Bread Cookie Sandwiches

INGREDIENTS

• 1 cup all-purpose flour
• 1 1/4 teaspoons ground cinnamon
• 1/2 teaspoon baking soda
• 1/2 teaspoon baking powder
• Coarse salt
• 1 1/2 sticks unsalted butter, room temperature
• 1/2 cup granulated sugar
• 1/2 cup packed light-brown sugar
• 1 large egg
• 1/2 teaspoon pure vanilla extract
• 1 cup finely grated zucchini
• 1 cup old-fashioned rolled oats
• 1/2 cup chopped toasted walnuts
• 8 ounces cream cheese, room temperature
• 1 cup confectioners' sugar, sifted