1. Combine Greek yogurt, minced garlic, lemon juice, olive oil, salt, and pepper in a bowl. Add chicken thighs and coat well. Marinate in the fridge for at least 30 minutes.

2. Toss diced potatoes with olive oil, sage, salt, and pepper. Spread them with chestnuts on a baking sheet and roast at 425°F for 30-35 minutes until golden and crisp.

3. Sear marinated chicken in a hot skillet over medium-high heat until golden and fully cooked. Let rest and slice.

4. Sauté mushrooms in olive oil until tender. Blend them with basil, garlic, olive oil, Parmesan, and a splash of cream to make mushroom pesto.

5. In a saucepan, simmer heavy cream with Parmesan and roasted garlic. Stir in mushroom pesto to make the Alfredo sauce.

6. Cook fettuccine pasta until al dente. Reserve 1/2 cup of pasta water and drain.

7. Toss pasta in the Alfredo-mushroom sauce, add pasta water as needed. Top with chicken slices, roasted potatoes, and chestnuts. Garnish with basil or extra Parmesan.