Take a baking tray / sheet pan with sides (see my notes for sizes etc) and pile pumpkin, onion, bacon & tomatoes in the middle of the tray, drizzle over olive oil and mix with your hands to coat, then spread out as evenly as you can (see notes). Bake for 20 minutes.
While the pumpkin mixture is baking, mix together the cream & mustard and set aside.
Meanwhile, cook pasta according to packet directions.
Remove baking tray from the oven, scatter pine nuts roughly over the pumpkin mixture. Now pour the cream & mustard mixture straight on to the baking tray, making sure to get all the mustard on to the tray (see notes).
Bake for a further 2 minutes.
Once finished baking, add pumpkin & cream mixture to the cooked pasta along with the basil leaves and mix everything to coat.
Taste test for salt and pepper at this point and add if necessary, and serve immediately with fresh parmesan.
Notes
My baking tray (I don't as yet own a sheet pan - not really something I have seen here in Australia but I'm eyeing off some on Amazon!) measures 25 cm x 37 cm or approx 9.5" x 14.5" (base measurement) - I would think this would be about the minimum to fit it all on the tray. That being said, my oven is only JUST wide enough to fit that 37 cm tray! The sides of my tray are approximately 1.5 cm or ¾" high.The sides of the tray don't need to be very high at all (in fact you don't want the sides to be too high or your pumpkin mixture will steam rather than bake).You could of course use 2 trays and divide it all in half - this would work fine but you may need to rotate the trays during the first 20 mins depending on if you have to put them on separate shelves, and your oven.When I spread the pumpkin mixture onto the baking tray, I like to roughly separate the "leaves"? of the onion wedges so they cook evenly. Plus I like the way you get the different texture and flavour when the onion has crisped up a bit, like in the photo with the pour shot.I don't even spread the cream out as I pour it - it naturally runs towards the edge anyway. And because the cream mixture only goes into the oven for 2 minutes, it will only really caramelize and thicken up at the edges. This is fine, because when you mix it all together with the pasta it combines to a lovely textured mustard cream sauce.I leave it until the end to check for salt and pepper because it depends on how salty your bacon is.Lastly, you can of course use any pasta you like. I go with angel hair because it's so quick cooking.*Please note that the amount of calories per serve is provided as a guide only, as ingredients and cooking methods can vary greatly*