Dairy-free, soya-free replacement for sour cream/yogurt in a pastry recipe

[ILoveAFullFridge]

Recipe is 3 yolks, 3tbsp sugar, 150g marge, 175ml sour cream or yogurt, 350g self raising flour.

It makes a very workeable dough that can be rolled out very thinly, and puffs up quite crunchily when baked.

What can I use to make it dairy-free and soya-free?

If it's the soured dairy product that gives the texture, can I make my own acidophilus culture using probiotics and dairy-substitute?

I've used coconut milk before to make a dairy free pastry, of course that does leave it with a bit of a flavour so it depends what you're going to be using the pastry for as to if it'll be suitable.

Oatly do an oat cream. I've use that before and seems ok. It's just as thick as soya cream.

Ah yes, I've seen the Oatly 'cream'. I wonder whether it can be cultured with acidophilus?