I have checked the Lonely Planet recommendation for Northern Jutland and they recommend one beach ahead of the rest. The beach at Tornby Strand.

It is a bit of a drive up to the beach of Tornby Strand – strand actually means beach in Danish. But if this is truly the best beach in northern Jutland it might be worth going up here and see what it is like. At least the drive is pretty fast along the country roads of the area which has very limited traffic. We get up to the beach fairly quickly.

The beach up here is a nice sandy beach which stretches for miles in both directions. So yeah it is a decent beach – but the west coast of Jutland has hundreds of kilometers of sandy beaches so I don’t find the beach up here anything particularly special. The beach in Blokhus where we are staying for a week is at least as nice as this lonely stretch of sandy beach – though you have to take care of the cars driving along the beach in Blokhus.
Cars on the beach Hmm brave to try the water this time of the year The North Sea at Tornby Strand
I guess it is the typical Lonely Planet recommendation which just take a random beach and say it is the best despite the fact there is a lot of other beaches around the area which is at least as nice.