[ConfusedGardener]

A few of my tomatoes, especially Big Zak (a "Beef-steak" type hybrid) are producing these twisted flowers which seem to be multiple flowers in one so to speak. Are they going to produce good tomatoes, or should they perhaps be pinched off?

[Springlands]

Beefsteak tomato plant flowers quite often look like that - first time I saw it I thought something was wrong. So just leave the flowers to develop and I hope you get a good crop. 

[mumofstig]

The multiblooms often produce toms that have 'catfacing' on their bottoms.
If you don't mind the big, but misshaped toms, then just grow them on. For more regular shaped tomatoes, they can be removed

[ConfusedGardener]

Thanks for the replies Springlands and mum,

I'll leave them on then. Looks like it should be a good yield this year... if the blight does not return!