I found this online somewhere and my son has taken to it with ease.  Super simple recipe

 

1 can full fat canned coconut milk, chilled not shaken

2 Tablespoons white vinegar

 

Put the cream from the can and put in a bowl and pour off the liquid.  You can save this to use in smoothies.  Stir in the vinegar, till fully incorporated.  Store in fridge.

That is all.

 

Dairy Free Sour Cream