So my mother in law had to comment full snark on my knife work, dicing green peppers and onions
Making pepper steak green peppers diced onion over rice.
I find humor in her as my wife they are so much alike.
Mother in law - Where did you learn how to chop vegetables, I know my daughter did not show you the way you are using knife , she continued in telling me the vegetables are not uniformed.
Me - My knife skills yea I learned them fort benning Georgia, bayonet course thrust parry kill . Then I held hands up showing the queen of sarcastic snark all ten fingers. So I handed my mother in law the bag of rice and a knife and said show me how to do it the uniform dicing I do love the woman. 
= new reply since forum marked as read
I'm just thankful they're doing it.
I really hardly ever cook anything for anyone else anymore. Thanks to my poor skills at being a mom 
, my kids all learned how to be pretty good cooks.
When I met my now-ex-husband, I told him, "I don't cook". I didn't want him to expect too much. The first time I made him a big breakfast he said, "I thought you said you couldn't cook!" I replied, "No, I said I don't cook." Big difference. The truth is that with all of the years I worked in food service, I actually do know what I'm doing.
The next time your MIL criticizes the uniformity of your prepping, you should tell her it's ok. She can use her teeth to chomp the food to just the right size when she's eating it. 
