Can Muslims eat food cooked by a woman on her period?

Her body isn't impure

In Islam, a woman on her period is excused from prayer and fasting and doesn't have intercourse with her husband. But she is not "dirty" in herself. Her skin, sweat and hands are pure. Only the menstrual blood itself is impure, and that's dealt with by normal hygiene, like any cook washing her hands. See Do I have to pray while on my period?

What the Prophet ﷺ did

Aisha said that when she was menstruating she would drink from a cup and hand it to the Prophet ﷺ, and he would put his mouth exactly where hers had been and drink. She would bite meat from a bone, and he would take it and eat from the same spot (Sahih Muslim 300). He also rested his head in her lap and recited the Quran while she was on her period (Sahih al-Bukhari 297).

Anas reported that some people in Madinah at that time would not eat with a menstruating woman or stay in the same house with her. When the companions asked about this, the Prophet ﷺ told them to do everything with their wives except intercourse (Sahih Muslim 302). In other words, Islam deliberately rejected the idea of isolating women during their periods.

Cultural myths to let go of

You may hear from relatives or older traditions that a woman shouldn't cook, touch pickles, bake bread or enter the kitchen during her period. These ideas don't come from the Quran or the Sunnah. A Muslim woman can:

• Cook for her family, guests or the whole iftar table.
• Bake, knead dough and handle raw meat.
• Say "Bismillah" before cooking and eating. See What dua do I say before eating?
• Do dhikr and make dua while she works. See Can I do dhikr on my period?

Normal kitchen hygiene still applies

Everyone who cooks should wash their hands, especially after using the bathroom or changing a pad, tampon or cup. That's simply good food safety, the same rule for men and women, on a period or not. Nothing more is required.