My search for the Pumpkin Lasagna that I remember has been unsuccessful; even a request to the source didn't come up with exactly what I was looking for... the one that I remember. She sent a LOT of other great, savory squash recipes, though, and is one of the few people I know who is an actual Gourmet Cook, so it's entirely possible she just made it on the fly with whatever she had that day.
I made this: Butternut Squash Lasagna*
I used acorn squash instead, because that's what I had. I partially cooked it this afternoon, in the same manner that I'd cook a pumpkin (halved, cut-side-down in a pan w/1/4-inch of water at 350F) and then stored it in the 'fridge until I was ready to assemble. Lemme just say that acorn squash isn't really something you want to peel. I sliced one and then cut off the shell, but mostly I just scooped it out as slab-like as I could. There's that to keep in mind. I used two small and one large squash.
I used a combo of grated mozarrella and gruyere, and didn't use the Sage/Lemon Brown Butter, but otherwise followed the recipe and IT WAS SO GOOD! I had to share... and record what I did before I forgot.
The recipe in my mind did not use lasagna noodles, did not have meat of any kind, and the squash was not mashed, pureed or cubed -- it was sliced. It took a few intensive searches to finally find the recipe above, and I found it on Pinterest! Yay!!
*No photo... that time of year is here! It is my goal, before too long, to have a semi-permanent lighting set up that I can haul around to wherever in the house I'm working... sewing in the front room, knitting in the living room, cooking/dyeing in the kitchen (never at the same time), whatever, wherever!