Preheat the oven to 400℉.
Slice the tops off the garlic bulbs. Drizzle the exposed tops with approx. a tsp of olive oil, and wrap each bulb in aluminum foil. Place the wrapped bulbs in the oven for 35-40 minutes until the garlic is soft and fragrant. Remove them from the oven and allow them to cool for a few minutes before extracting.
Prepare the pasta as per packaging in salty water. When done drain and set to the side.
In a pot, melt the butter over low-medium heat. Once melted, add the extracted roasted garlic. Break up the cloves with the back of a spoon and mix them in with the melted butter.
Add the flour and mix to combine. Cook for 2-3 minutes, then add the miso and mix to form a paste.
Pour in the turkey broth and whisk to combine; this may take a minute or two. Cook for 1-2 minutes until it has thickened up.
Add the heavy cream and bring to a simmer. Careful to not bring to a boil especially if swapping out for half and half.
Reduce the heat to low and add in the freshly grated cheddar cheese. Mix into the sauce until it has completely melted. Salt to taste if necessary.
Turn off the heat. Add in the pasta and toss to coat in the cheese sauce. Serve immediately.