Make sure to use Almond Flour. It is not the same thing as Almond Meal. Bob’s Red Mill Superfine Almond Flour is my go-to.
Your egg whites can, but do not need to be at room temperature.
Using whipped cream cheese in the filling makes a lighter icing but standard cream cheese works as well.
There are two things that can help ensure the success of macarons. First, make sure you are deflating the batter only to the lava stage. If you don’t deflate enough, the batter will be too thick and your macarons will have peaks (typically called nipples). If you deflate too much, your batter will be too runny and the macarons won’t rise properly. Secondly, using an oven thermometer is highly encouraged. An oven that is too hot will cause the feet on the macarons to spread and result in hollow shells. An oven that is too cold will result in wrinkly, undercooked macarons.