I have made these twice subbing almond flour for the ground walnuts. They are delicious, but no crackly brownie top! Any ideas why that is? I weighed

Hi Terry! Switching to almond flour shouldn't affect the crackly top. According to Shirley O. Corriher in her book Bakewise, whether brownies "have a crust on top depends on how much you beat the batter after the eggs are added." That's why, in this recipe, I say to mix for 2 minutes after the eggs are in. In recipe developing and testing, this reliably produced a shiny-crackly top for us. But if that's not working for you with the almond flour, it couldn't hurt to mix a little harder or longer. Hope that helps!