I’m dying to try these but don’t have any spelt flour at home. Could I substitute white?

Thanks, BakerBren. Would say exactly the same.

You should be able to substitute AP white wheat flour for the spelt flour in these with little change since there's also rye flour and other additions. If you have it, a weaker pastry flour would be closer in behavior to the spelt flour. Pay attention to the texture of the final dough as it will absorb liquid and hold its shape slightly differently from the spelt flour.