Butternut!Make sure your knives are sharp sharp sharp!
Trying to prepare butternut with a blunt or inadequate knife, or even a peeler, is horrible. I remember tring to prepare a butternut in a rented cottage, where the only knife available was a cheap and flimsy 4" serrated vegetable knife, and after five minutes wrestling and nearly losing several fingers I was ready to throw the thing through a window.
Use the biggest, sharpest, most robust knife you possess! Slice off the very top of the squash and then cut the butternut in two at the top of the "bulge", so that you end up with a cylinder and a sphere, then just slice down the sides of the cylinder with a sharp knife.
Cut off the bottom of the sphere so that you've got a flat base, slice off the peel at an angle, top half first, then turn the sphere upside down and do the same to the bottom half. Easy-peasy - halve it, quickly scrape out the seeds with a spoon, and you're done.
I love your idea of fennel seeds. Butternut is a favourite of mine: peeled, boiled and mashed, with butter and maybe some ground nutmeg or allspice. It's wonderful peeled and baked in chunks, until it begins to caramelise, with butter and Indian spices - either a teaspoon of masala spice scattered over it, or simply a couple of crushed cardamom pods, a teaspoon of whole cumin or mustard seeds, and a cinnamon stick. I've also made a very tasty butternut curry to a recipe by Madhur Jaffrey, with chillies, peppercorns, fenugreek, brown sugar and cumin.
For summer chunks of seasoned butternut are great baked in the ashes of a barbeque, or threaded in smaller pieces onto skewers with aubergine, mushroom and red pepper and roasted as a vegetable kebab.
I've baked sweet potato with bitter orange marmalade and orange juice, and I wonder if butternut might work well with orange as well?
And butternut makes one of the most satisfying winter soups: sweet and unctuous, with an intense orange colour and velvet-smooth texture. Two nights ago I made soup from butternut - simply pureeing the butternut with vegetable stock and adding a tablespoon of cream.