• Preheat your oven to 350°F (175°C) and prepare a baking sheet with aluminum foil.

For the Bread Mixture:

• Place the bread cubes on the baking sheet. Bake for 20 to 30 minutes until thoroughly dry. After baking, transfer to a bowl.
• In a large skillet over medium-high heat, cook the bacon until crispy, about 10 minutes. Once done, move bacon to one side and discard excess grease.
• With the heat still on, add the onions and peppers to the skillet. Sauté for a few minutes until softened, then add garlic and cook until fragrant.
• Add reserved clam juice and cook until reduced by half, stirring continuously for about 3 to 5 minutes.
• Combine the skillet mixture with the bread cubes in the bowl. Stir in clams, ricotta, 1/2 cup of the Parmigiano-Reggiano, parsley, salt, pepper, and cayenne. Cover and refrigerate until ready to use.

For the Sauce and Assembly:

• In a new skillet, melt butter over medium-high heat. Once melted, whisk in flour and cook until lightly browned, about 2 minutes. Add in milk and continuously whisk until smooth and beginning to simmer.
• Remove from heat, reserving 3/4 of the sauce in a baking dish. Keep remaining sauce aside.
• In a large pot, bring salted water to a boil. Cook the pasta shells for about 9 minutes until 75% cooked. Drain and cover with cold water to keep them moist.
• Raise oven temperature to 400°F (200°C).
• Stuff the shells with the bread-clam mixture, arranging them over the reserved sauce in the dish. Drizzle with remaining sauce and top with the rest of the Parmigiano-Reggiano.
• Bake for 30 to 40 minutes until the pasta is tender, sauce is bubbly, and cheese is golden. Optionally, garnish with additional parsley before serving. Enjoy your delightful dish!