I do not, but Alanna Taylor-Tobin does! In her Homemade Pumpkin Puree (with No Pumpkin!), she's using butternut squash, but specifically offers kabocha as an alternative, saying: "Less fibrous and with a lower water content, kabocha squash puree is more dense, firm, and has a deeper, more earthy flavor."
Re: Let's hear it for empiricism!
I do not, but Alanna Taylor-Tobin does! In her Homemade Pumpkin Puree (with No Pumpkin!), she's using butternut squash, but specifically offers kabocha as an alternative, saying: "Less fibrous and with a lower water content, kabocha squash puree is more dense, firm, and has a deeper, more earthy flavor."