For the Meatballs
8 oz white button or cremini mushrooms, cleaned, stems trimmed and roughly chopped
2 tbsp olive oil, divided use
1 tbsp unsalted butter
2 cloves garlic, minced
1 large egg
1 1/2 tbsp low sodium chicken stock
1/4 tsp unflavored gelatin powder
1/2 lb ground turkey
11/2 tsp balsamic vinegar
1 tsp lemon zest
1 1/2 tbsp finely ground breadcrumbs
2 tbsp grated Parmesan, plus additional for garnish
Kosher salt and black pepper
For the Sauce
1/2 c dry sherry
1/3 c all-purpose flour
1 c low-sodium chicken stock
3 1/4 c milk
1 c heavy cream
1/8 tsp ground nutmeg
1 lb linguine, cooked al dente
1/4 c torn fresh basil
Pulse mushrooms in a food processor until finely and evenly chopped.
Melt 1 tablespoon olive oil and butter in a large saute pan over medium-high heat. When the mixture begins to foam, add mushrooms and allow to cook, untouched in a single layer, for 4 minutes. Reduce heat to medium, stir and add garlic on top. Continue cooking for an additional 2 minutes. Stir again and saute for one minute more. Remove from heat, transfer mushrooms to a large bowl and let cool.
Whisk together egg and chicken stock in a small bowl. Sprinkle with gelatin and let rest for 5 minutes. Then, whisk to combine and add egg mixture to cooled mushrooms, along with turkey, balsamic vinegar, lemon zest, breadcrumbs, Parmesan, 1/2 teaspoon salt and 1/2 teaspoon black pepper. Combine using hands, taking care not to over-mix. Form mixture into golf ball-sized balls.
Heat remaining tablespoon of olive oil in a large saute pan over medium-high heat. When oil shimmers, add meatballs. Brown on all sides, working in batches, if necessary, so you do not overcrowd, about 5 minutes total. Transfer meatballs to a platter.
Add sherry to the pan and scrape up the browned bits using a spoon.
Whisk together flour, chicken stock and milk in a large bowl, ensuring there are no lumps. Pour into the pan, along with heavy cream, nutmeg, 1 1/2 teaspoons salt and 3/4 teaspoon black pepper. Bring to a boil over medium heat and add meatballs so they can finish cooking in the simmering sauce.
When meatballs have finished cooking and the sauce has thickened, ladle atop linguine and garnish with basil and Parmesan.