Bring a large pot of water to a boil.
Meanwhile, make the peanut sauce by whisking together the peanut butter, garlic clove, maple syrup, tamari, vinegar or lime juice, and warm water in a medium bowl. If the sauce is too thick or seizes up, add additional warm water. Taste and add additional tamari if you prefer a saltier sauce, maple syrup if you like it sweeter, or vinegar/lime juice is you prefer it tangier.
When the water boils, add the pasta and cook according to package directions. Remove the pasta from the water, leaving the water in the pot.
To the same boiling water, add the broccoli and cook for 2-3 minutes, until just tender and bright green, being careful not to overcook. Drain the broccoli and rinse with cold water to stop the cooking process.
In a large bowl, toss together the cooked pasta, broccoli, cabbage, carrot, and scallions. Drizzle with the peanut sauce and toss again, until the pasta and veggies are coated with the sauce. Serve with peanuts and hot sauce if you like.