Pre-heat your oven to 400 degrees. Put a large pot of water on to boil.
Heat 1 tablespoon olive oil in a large skillet or sauté pan over medium heat. When hot add the shallot and garlic and cook for 3 minutes until the shallots become translucent and the garlic is fragrant. (Be very careful not to burn the garlic peeps!)
Add the sausage to the pan and cook, breaking up the meat with a spatula, for 5-6 minutes until lightly browned. Remove the skillet from the heat and set aside.
Add the orzo to the boiling water. Cook for 6 minutes and then add the broccolini to the pot. Cook for 2 more minutes and strain immediately.
Add the orzo and broccolini to the skillet with the sausage. Set aside while you prepare the cheese sauce.
Heat the remaining 3 tablespoons olive oil in a medium saucepan over medium heat. When the oil is hot and shimmering, whisk in the flour. Cook your roux, whisking constantly, for 3 minutes. Add the chicken stock, increase the heat to medium-high, and bring to a boil, whisking periodically (about 2-3 minutes). Lower to a simmer, and cook for 4-5 minutes, whisking continuously until the liquid is thick enough to coat the back of a spoon. Turn off the heat and add the Fontina. Whisk until fully incorporated and then whisk in ¼ cup grated Pecornino Romano, the red pepper flakes and lemon zest. Taste and add a little salt if necessary.
Pour your cheese sauce over the orzo mixture and stir to combine.
Transfer the orzo to a casserole dish and top with the remaining ¼ cup Pecorino Romano and the Panko breadcrumbs. Bake for 25 minutes until the top is golden brown and the cheese is bubbling.
Spoon orzo into bowls and serve warm.