If saying “thank you” feels weird or awkward, you can use language that is more natural and common between yourself and your parents.
If they see you as aloof and a bit distant, you can say indirect statements to complement her food like “this really hits the spot!” or “better than __________” (fill in a well known upscale restaurant name). Pretend you’re talking to yourself out loud (in an audible tone so that she can hear).
Your mom will get it, and she will really appreciate the complement, however indirect.
It’s very hard and awkward to try to change the dynamics in a relationship. Sometimes, with the passage of time, gradual changes in interaction become normal.