Preheat oven to 400°F (200°C). Line a sheet pan with parchment paper. Have a rolling pin and pizza cutter or sharp knife ready.

In a microwave-safe bowl, combine shredded mozzarella and cream cheese. Microwave in 30-second bursts, stirring between each, until fully melted and smooth (about 1-1½ minutes total). Let cool 1 minute.

Add almond flour, egg, garlic powder, and xanthan gum (if using) to a food processor. Pour in the melted cheese mixture. Pulse until a uniform dough ball forms, scraping sides as needed. If too sticky, add 1 tablespoon more almond flour.

Transfer dough to a sheet of parchment dusted with almond flour. Pat into a rectangle, top with another parchment, and roll to 1/8-inch thickness. Remove top parchment and cut long fettuccine-style strips about ¼-inch wide using a pizza cutter.

Carefully transfer the cut noodles to the prepared sheet pan, separating them gently. They may stick slightly; use a spatula. Bake 5-7 minutes, or until internal temperature reaches 160°F (71°C) and edges are just golden. Remove and set aside; they will continue to firm up.

While pasta bakes, melt butter in a large skillet over medium heat. Sauté minced garlic until fragrant, about 1 minute. Pour in heavy cream, bring to a gentle simmer, then whisk in Parmesan, salt, and pepper. Stir until smooth and thickened, 2-3 minutes. Keep warm.

Add the par-baked noodles to the skillet with Alfredo sauce. Toss gently with tongs over low heat for 1-2 minutes until noodles are well coated and heated through. If sauce is too thick, add a splash of hot water.

Divide among four warm plates. Twirl each portion into a nest, top with extra Parmesan, black pepper, and parsley. Serve immediately.