Step 1 Boil the pasta to al dente according to the instructions on the packaging. Drain the pasta well and spread it out on a rimmed baking sheet, very lightly oiling the pasta to keep it from sticking. Set aside and heat the oven to 375 degrees.
Step 2 In a large, heavy-bottomed saucepan, melt 2 tablespoons butter over medium-high heat. Stir in the chopped onion and cook, stirring occasionally, until the onion is softened and lightly browned, 10 to 15 minutes.
Step 3Stir in the hard cider, scraping to dislodge any flavorings from the base of the pan. Bring the cider to a simmer.
Step 4Add the cheese, a few cubes at a time, stirring to melt. When the cheese is mostly melted, stir in the milk. Once all of the cheese is melted and the ingredients are thoroughly incorporated to form a sauce, stir in the cooked pasta. Season with the salt and several grinds of black pepper, or to taste.
Step 5Spoon the pasta and sauce into a 11/2- to 2-quart gratin dish.
Step 6To make the topping, melt the remaining 3 tablespoons butter, then stir in the bread crumbs and grated Gouda cheese until evenly combined, with the bread crumbs lightly coated with butter. Taste and add a pinch of salt, or as desired. Sprinkle the topping over the pasta.
Step 7Bake the macaroni until the sauce is bubbly along the edges and the topping is crisp and a light golden color, 12 to 15 minutes. Remove from heat and cool slightly before serving.