Fast Food

In-N-Out is being grilled with a religious discrimination lawsuit ... a former cook says the company treated her differently and ultimately fired her after she asked for a different work schedule due to her Christian beliefs.

According to the suit, obtained by TMZ, Arianna Rodriguez said she had been working as a cook for the burger chain's Long Beach, CA location for nearly 5 years without issues with a schedule that allowed her to attend church on Sundays.

She claims this wasn't an issue until a new manager started in October. She alleges her Sunday availability then became a "recurring source of workplace conflict," and she got her first-ever write-up during this time.