Use heavy duty aluminum foil to tightly wrap the bottom and sides of a 9" springform pan, paying special attention to completely cover the bottom and side seams, so that no liquid escapes (you don't want THAT mess). Place the pan on a sheet pan lined with foil or parchment paper and set aside.
Preheat the oven to 375°. Place the bell pepper on a foil lined pan and roast for 30 minutes or until the skin is blackened and puffy and the pepper is tender. Transfer the pepper to a small bowl and cover tightly with plastic wrap to cool. Set aside.
While pepper is roasting, cut the tomato in quarters and remove all the seeds and juice. Set the tomato in a small bowl lined with a paper towel and sprinkle lightly with salt. Set aside.
Peel the skin from the roasted red pepper and remove the stem and seeds. Pat each piece completely dry with a paper towel and dice the pepper. Set aside.
Heat a skillet over medium high heat and add the raw sausages. Cook the linguiça sausages to render the fat and sear the skin, turning occasionally so that every side gets browned, about 5-8 minutes. Transfer the sausages to a plate to rest. (Note: sausage will not be completely cooked through, but they will finish cooking in the oven).
Add the chopped onion to the pan with the sausage fat and sauté for 3-5 minutes until tender and the onion has picked up the flavor of the sausage. Set aside.
Bring a large pasta pot, filled halfway with water to a boil. When water starts to boil add a tablespoon of salt. Water will boil even more furiously. Add the pasta and cook to 2 minutes BEFORE the pasta is done. This is before al dente -- the pasta will continue to cook in the oven and will soak up the liquids in the dish). Drain the pasta and transfer it back to the same pot it was cooking in. Drizzle with the olive oil and toss to coat.
Add the raw spinach to the hot pasta and toss. The pasta will wilt the spinach naturally. When the spinach has wilted, add the diced tomato, sautéed onion, diced, roasted red pepper and grated swiss cheese. Toss to combine using a pair of kitchen tongs.
Slice the sausages in half lengthwise and cut them into 1/2" pieces. Add the sausage to the pasta mixture.
In another bowl whisk together eggs, milk, half and half, salt and pepper. Pour the mixture over the pasta and toss well with the tongs until well combined.
Spray the springform pan liberally with vegetable spray. Transfer the pasta mixture to the prepared springform pan and smooth out the top. Sprinkle with extra parmesan cheese.
Bake for 30 minutes, then rotate the pan 180° in the oven and continue to bake for 15-20 minutes longer or until pie is solid and no egg juices bubble up from the center when tested with a knife.
Remove the pie from the oven and let rest for 10-15 minutes before removing the foil. Any remaining juices should settle back into the dish. Run a sharp knife around the edges of the pan so the edges of the spaghetti pie don't stick to the collar. Open the collar and carefully remove.
Place a plate on the top of the pie and in one swift move, flip the pie upside down onto the plate. Place the platter you'll be serving the spaghetti pie on, centered on the bottom part of the pie and flip once again so the crispy top is again right-side-up. Serve.