Preheat your oven to 350 degrees.  Line an 8X8 pan with parchment paper and spray with non-stick cooking spray.To make the blondies, combine melted butter and brown sugar in a large mixing bowl. Add in the large egg and vanilla, whisk to combine.Next, add the flour, cinnamon, baking powder, and kosher salt to the egg mixture. Fold in the shredded carrots. The batter will be thick, but I promise it will spread!To make the cream cheese swirl in a large mixer fitted with a paddle attachment combine all the ingredients until fluffy.Take half of the blondie batter and smooth it out into the bottom of the prepared baking dish. Next, take half of the cream cheese mixture and spread it on top of the carrot batter. Cover the cream cheese with the remainder of the carrot batter. Dollop the remaining cream cheese on top and use a sharp knife to create swirls. You don’t have to do the swirls if you don’t want to! You can simply just spread the remaining cream cheese mixture over the carrot batter.Bake until the bars are set (start to pull away from the sides) and a tooth pick inserted in the middle comes out clean; about 35 minutes. I would check at the 30 minute mark just to make sure. The batter for me took about 36 minutes and I used a glass dish. Remove the pan from the oven and let it cool completely before slicing.To make the glaze (again optional), whisk together sugar, milk, and lemon juice. Pour it over the blondies, slice into squares, and enjoy!