Add dried spaghetti to a large pot, off the heat, breaking noodles in half.
10 oz spaghetti pasta
Remove the stems of the portobello mushrooms. Using a spoon, carefully scrape out the gills, making sure not to damage the rim of the mushrooms. Dice mushrooms into ½-inch cubes and add to the pot.
Trim and discard the ends of the zucchini; small dice the zucchini into ½-inch cubes and add to the pot.
Peel and mince or press the garlic; add to pot.
4 cloves garlic
Remove the stem ends of the green onions. Slice in ¼-inch pieces and add to pot.
Slide the thyme leaves off the stems; discard the stems, add to the pot. Add butter and season everything with salt and pepper.
2 tsp salt
¼ tsp black pepper
1 tbsp butter, unsalted
Add enough water to the pot just to cover noodles. Bring to a boil over high heat, then reduce heat to medium; water should remain at a low boil for the entire cooking process.
Ensure pasta is mostly submerged in cooking liquid while cooking. Stirring frequently, simmer, uncovered, until pasta is cooked through, vegetables have softened and liquid has reduced. About 8-10 minutes.
Finely grate Parmesan.
8 oz Parmesan cheese
When pasta is done cooking drain any excess liquid from the pot using a colander.
Return pasta and veggies to the pot. Stir in heavy cream and Parmesan. Serve immediately. Enjoy!