Step 1

In a small mixing bowl, whisk together 1  1/2 cups milk, 1 cup mayonnaise, brown sugar (1 tablespoon), salt (1 teaspoon), and black pepper (1/2 teaspoon). Set aside.

Step 2

In a large pot, bring 4 quarts of water to a roiling bowl. Add pasta (1 pound) and 1 tablespoon of salt to the water and cook the pasta for 15 minutes, until it's fat and very soft. Drain the pasta and pour it back into the dried pasta pot. Pour vinegar (1/4 cup) over pasta and stir until it's evenly distributed and absorbed. Pour pasta into a bowl and cool for 10 minutes. Add the milk and mayonnaise mixture and stir until evenly combined, then cool completely.

Step 3

Add the grated onions (1/4 cup), carrots (1/2 cup), celery (1/2 cup), (ham, pineapple, green onion~if using), and the remaining milk (1/2 cup) and mayonnaise (1 cup) to the pasta and mix until evenly distributed. Cover and refrigerate for at least 1 hour for up to 2 days. Adjust seasoning if necessary and serve.