Cook the whole wheat macaroni in a large pot of boiling salted water according to package directions until al dente, then drain.
In a separate medium saucepan, simmer the cauliflower florets in the vegetable broth over medium heat until tender, approximately 8 to 10 minutes.
Transfer the cooked cauliflower and any remaining broth into a high-speed blender and process until completely smooth.
Return the cauliflower puree to the saucepan over low heat and whisk in the Greek yogurt, shredded cheddar cheese, garlic powder, onion powder, and smoked paprika.
Continue whisking until the cheese is fully melted and the sauce is smooth and creamy.
Fold the cooked macaroni into the cheese sauce until thoroughly coated.
Season with salt and black pepper to taste and serve immediately.