Learn Danish: Begge ingredienser blandes i skålen. - Both ingredients are mixed in the bowl.

This is the present tense s-passive. To make it, you take the infinitive verb blande (to mix) and add an -s to the end. It means "are mixed" or "are being mixed".

Could I say bliver blandet instead of blandes?

You could, but blandes is much more natural here. The s-passive is the standard choice for written instructions, such as recipes or manuals. The passive with bliver is used more often in spoken Danish to describe an action happening right now.

Why does ingredienser have an -er ending?

The word begge means "both", which implies more than one. Therefore, it must be followed by a plural noun. Ingredienser is the plural form of en ingrediens.

Why does skålen end in -en?

The dictionary form is en skål (a bowl). Because we are talking about a specific bowl from our context, we attach the -en to the end of the word to make it skålen, meaning "the bowl".