Position a rack in the center of the oven and heat the oven to 375°F. Butter a 9x13-inch baking dish.Bring a large pot of well-salted water to a boil and add the pasta; cook according to package directions until al dente. Reserve 1/2 cup of the pasta water, drain the pasta well, and return the pasta to the pot.
Meanwhile, for the cheese sauce, melt the butter in a medium (3-quart) saucepan over medium heat. Add the shallot, sprinkle with 1/4 tsp. salt, and cook, stirring occasionally, until it softens and becomes translucent, about 3 minutes. Add the flour and cook, stirring, until it turns golden and smells nutty, about 1 minute. Whisk in the milk in a slow, steady stream, and cook, whisking occasionally to avoid sticking on the bottom of the pan, until the mixture thickens, about 10 minutes. Remove from the heat and stir in all but 1/2 cup of Grana Padano, the thyme, 1-1/2 tsp. black pepper, 1/2 tsp. salt, and the Tabasco. Stir the ham and peas into the sauce; taste and add more salt and pepper if needed.
Stir 1/4 cup of the pasta water into the béchamel so it loosens a bit and then toss with the pasta in the pasta pot. Add more pasta water as needed. Transfer to the prepared baking dish. In a small bowl, mix the breadcrumbs, olive oil, 1/4 tsp. salt, and 1/4 tsp. pepper with the remaining 1/2 cup cheese, and sprinkle over the pasta. Bake the pasta until it bubbles and browns around the edges, about 20 minutes (cover with foil if the top browns too quickly). Let cool for a couple of minutes and then serve.