Preheat oven to 375°F.
Cook pasta in large pot of boiling salty water until al dente. Meanwhile, on low heat, melt butter, add flour cook, whisking, for 1 minute. Gently add hot milk while whisking continuously. Continue cooking on low heat while whisking until sauce starts to thicken. Season with salt and pepper.
Add Grand Cru and BellaVitano cheeses and mix well. Drain pasta and gently fold into sauce. Add fresh peas and chopped shells.
Slice top of tomatoes and scoop out center, taking care not to cut through the bottom. Lightly salt inside of tomato and divide pasta equally into tomato bowls.
Bake for 15 minutes. Sprinkle grated GranQueso over top; increase temperature to 400°F and bake for another 5 minutes. Remove, cool for 2-3 minutes and serve with light salad.