I can be that "Mommy Monster" at times which is SUPER out of character for me- I used to be known as 'the nicest person' and this is a new and strange territory for me.

Therapy helps, but I have suffered with double vision and sadly seeing "2" of my therapist was too hard on me to focus so I have turned to books to learn to cope.

Books:
Open Focus
The Power of Now
Yoga Nidra (as this teaches feeling opposite emotions and learning to control them through awareness)
and
The DBT workbook for Anxiety

Also taking a Time Out when I start noticing a rise in my frustration helps. I go for a long walk and don't come back until my mindset has changed.

Guided Meditation- Mindfulness for 15 minutes even if my mind wanders everywhere, changes my mental state allowing me to react differently to a situation.

Notice the Physical Sensations you feel with anger and changing your posture. Just like how they say putting a pencil in your mouth makes you 'feel' happier. Changing my furrowed brow to a more relaxed facial expression seems to help me.

Just keep at it. It's really difficult at times for sure- especially to become aware that you're doing it. But remember that you are not that behavior and it's just a bad habit you've picked up and know that habits can be changed with effort. Good luck!