Preheat oven to 375°F. Butter a 9x12 baking dish, set aside.
Cook pasta to al dente, according to package instructions. Drain and toss with a little olive oil to keep from sticking. Set aside.
In a large pot over medium heat, melt the four tablespoons of butter. Add the garlic and cook for about 30 seconds. Sprinkle flour over butter and whisk together. Continue to whisk for 2-3 minutes.
Very gradually, pour in milk while whisking. Start by adding a little milk at a time, then whisking to combine before adding more. This needs to be done slowly to keep the sauce from getting lumpy.
Once all milk is added, add the paprika, salt, pepper and nutmeg. Whisk to combine. Add the mascarpone and whisk until incorporated. Start adding the grated fontina, cheddar and parmesan, a handful at a time. After adding one handful, whisk until cheese is fully incorporated before adding more. Continue this until all cheese has been added. Add 2 tablespoons of truffle oil, whisk until fully incorporated.
Add the cooked pasta and stir to fully coat pasta with cheese sauce.
Pour noodles into prepared baking dish. Top with panko breadcrumbs. Drizzle remaining truffle oil over the breadcrumbs.
Bake in oven for about 35 minutes, until breadcrumbs are golden.
Remove from oven and allow to sit for about five minutes before serving.