Instructions

• Preheat the oven to 350°F (175°C). Line an 8×8-inch baking pan with aluminum foil and spray the foil with cooking spray; set the pan aside.
• In a large, microwave-safe bowl add ½ cup (1 stick) unsalted butter and microwave on high until melted, about 1 minute. Let the butter cool until warm but not hot (about 1–2 minutes) to avoid scrambling the egg.
• Add 1 large egg, 1 cup packed light brown sugar, 1 tablespoon vanilla extract, and 2 to 3 teaspoons cinnamon (use your preferred amount) to the warm melted butter. Whisk until the mixture is smooth and uniform.
• Add 1 cup all-purpose flour and ½ teaspoon salt to the wet mixture. Stir with a spatula or spoon until just combined; do not overmix.
• Turn the batter into the prepared 8×8 pan and smooth the top lightly with a spatula. Bake at 350°F for 20 to 24 minutes, or until the top is set in the center and a toothpick inserted in the center comes out clean or with a few moist crumbs. Do not overbake. Remove the pan from the oven and place it on a wire rack to cool for at least 90 minutes before frosting.
• To make the frosting, place 6 ounces softened cream cheese and ¼ cup softened unsalted butter in a large bowl or the bowl of a stand mixer. Beat until smooth and combined.
• Add 1½ cups confectioners’ sugar, ½ teaspoon vanilla extract, and ½ teaspoon salt to the cream cheese mixture. Beat with an electric mixer (or the paddle attachment) until the frosting is light and fluffy, about 2 to 3 minutes.
• Spread the frosting evenly over the completely cooled blondies using a spatula. You may have a small amount of frosting left over; extra frosting will keep airtight in the fridge for at least 2 weeks.
• Evenly sprinkle a little cinnamon over the frosted bars to garnish, slice into bars, and serve. Store the bars airtight at room temperature for up to 4 days or in the refrigerator for up to 1 week (refrigerated bars may dry out slightly; bring to room temperature before serving if desired).