In a large pot of boiling salted water, cook pasta according to package instructions; drain well.
Preheat oven to 400 degrees F.
Melt butter in a Dutch oven over medium heat. Add garlic and shallots, and cook, stirring frequently, until fragrant, about 2 minutes.
Whisk in flour until lightly browned, about 1 minute.
Stir in half and half and Dijon until slightly thickened, about 4-5 minutes.
Remove from heat. Stir in cheddar cheese until smooth, about 2 minutes.
Stir in pasta, tuna and green peas until well combined; season with salt and pepper, to taste; sprinkle with Panko mixture.
Place into oven and bake until golden brown and bubbly. about 25-30 minutes.
Serve immediately, garnished with chives, if desired.
In a small bowl, combine Panko, Parmesan, lemon zest and olive oil.
