Medievalists have probably already seen these; but if you’re not a medievalist, and like reading about how (other?) academics write, here are a couple of essays with food for thought.
My thought is that they’re not counting their preparation as “writing.” They wouldn’t get the manic bursts of thousands of words without the regular reading, planning, thinking that they both talk about. Sometimes I get such bursts, and they feel like a gift; but, physically, I can’t produce even 2000 words a day without pain. So I plod along, maybe not a tortoise by nature, though I’ve learned to act like one.
Both writers insist on knowing yourself and the way you work, which I think is good advice; and “know what you are and be it more” is great advice.