It's true that almond flour doesn't rise as easily as wheat flour, which is why it's important to use a recipe with the right ratio of almond flour to liquid so that your cookies don't end up flat. These soft almond flour lemon cookies are based on shortbread, so they're thicker and denser than many cookie recipes. So as long as you chill them as directed, you shouldn't have any issues with the cookies flattening out.