Hollow help

So I use Sally’s recipe for French macarons and I’m on batch 8. My meringue was super stiff, the batter mixed great, the shells piped great and they cooked nearly perfect but they’re hollow ☹️ I’m wondering if when I’m mixing the batter should I be smushing the batter on the sides to get the air out? Any thoughts? I did add color but this happened to the batch before them too and I used the master elite powder color and followed the instructions and nothing about it seemed off 😩