Great question — answering as the UphillTech team:
There's absolutely no reason to mix the egg in with the flour as opposed to the liquid ingredients, you will get the same result either way. I'd think if anything mixing the egg in with the liquid ingredients will get you a better mix. With no-knead bread you don't need a separate autolyse step as the long proofing time in the refrigerator gives plenty of time for all the enzymes and yeasts to do their thing. If you did want to convert this to a knead recipe then an autolyse step would be fine, I wouldn't withhold the egg though as getting it mixed in would be challenging, instead I'd mix in the egg with the rest of the ingredients and withhold the salt with a small amount of the water.
Full answer by GdD: https://cooking.stackexchange.com/a/136947 (CC BY-SA 4.0).
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