Swedish Meatball Pasta Bake

Name: Swedish Meatball Pasta Bake
Prep time: 45 min
Cook time: 1 h
Total time: 1 h 45 min
Cuisine: European
Ingredients: 2 cups small shell pasta, (uncooked); 4 Tbsp. butter; 2/3 cup yellow onion, (finely chopped); 1 1/2 tsp. kosher salt; 1/2 tsp. freshly ground black pepper; 1/2 tsp. ground allspice; 1/4 tsp. nutmeg; 3 cloves garlic, (minced); 2/3 cup milk; 1 1/4 cups plain panko bread crumbs; 1 lb. ground beef, (I use 80/20); 1 lb. ground pork; 2 large eggs, (beaten); 3 Tbsp. olive oil; 6 Tbsp. butter; 7 Tbsp. all-purpose flour; 4 1/2 cups low sodium beef broth; 1 Tbsp. Worcestershire sauce; 3 Tbsp. fresh parsley, (finely chopped); 1/2 cup heavy cream; 2 tsp. kosher salt; 2 Tbsp. butter; 1/3 cup yellow onion, (finely chopped); 3/4 tsp. kosher salt; 1/4 tsp. freshly ground black pepper; 1/4 tsp. ground allspice; 1/8 tsp. nutmeg; 2 cloves garlic, (minced); 1/3 cup milk; 1/2 cup plus 2 Tbsp. plain panko bread crumbs