Assalamu alaikkum...Am running a bakery. ..can I sale cakes in Christmas?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His Slave and Messenger.

As for things that are peculiar to the Christian holidays, such as if they prepared special cake particularly for their holiday, you may not make it and sell it to them.

Ibn Taymiyyah said,

“It is unlawful for Muslims to imitate (non-Muslims) in anything which is peculiar to their holidays, be it food, clothing, or bathing … (and it is also prohibited) to sell them anything which is used to assist them in that for that reason.” [Al-Fataawa Al-Kubra]

However, it is permissible for you to sell the regular types of food that are not peculiar to their holidays because it is permissible to engage in trade with idolaters. Please refer to fatwa 130135.

Allaah Knows best.