I have made this recipe for years...But, I use foil rolled up and in a circle and sit the squash in the middle to keep it level. I used to shave the bottom. But, i have found that the juices of the butter and brown sugar seep all the way through the squash and leaving a big mess. At least this way the juices stay in and has more flavor. I hope this suggestion is of help. But, be assured this is one of the BEST "acorn squash" recipes out there.
*Kuddo's to the one that posted this!!

I put my acorn squash in micro-wave for 10 minutes, carefully cut squash and remove seeds. Add butter and brown sugar. No mess, super soft, tastes like chestnuts.

I make this same dish but cut the top off as you would carving a pumpkin, remove seeds and pulp, put butter and brown sugar in the squash, replace the top, place on pie plate and pop it in the oven. When it's done spoon out the squash and mash. Same temp. and ingredients.

I add cinnamon to mine, along with the butter & sugar.

Yes! Some black pepper too.

I have never cooked or had acorn squash. Wow! This recipe was awesome! I shared our meal with a neigbor in our bldg. she came back for the recipe for the squash recipe! I am making this again today! I woul not change a thing! We love it!