PREP: This dish moves quickly; prep first! Start by measuring the milk and setting it aside (warmer milk = cooks faster). Dice onion (use food processor for quicker prep). Prepare sausage (Note 1).
ONION AND SAUSAGE: Heat 1-1/2 tbsp oil in a large nonstick pot over medium-high heat. Add onion, and sauté 3 minutes. Add prepared coined sausages and cook, stirring/flipping only occasionally until golden and nicely browned on the outside. (Don't constantly stir; we want to get a nice char!) While browning, season the sausage to taste (I add 3/4 tsp salt & 1/4 tsp pepper). Once sausage is cooked through, add in frozen peas and 1 tbsp garlic. Sauté for 2 minutes. Empty all of the mixture into a large bowl; cover with foil and set aside for now. Don't wipe out the pot.
CREAM SAUCE: Return the pot to the burner, set to medium heat. Melt 2 tbsp butter, whisk in 2 tbsp flour. Cook and stir for 1 minute. Gradually, while whisking constantly, add in 2 cups stock. Add in 2-1/4 cup milk, uncooked 1-1/2 cups orzo, 1 tbsp Italian seasoning, 1/2 tsp garlic powder, and 1/2 tsp onion powder. Stir.
FINISH COOKING: Raise heat to bring mixture to a simmer, then lower the heat until it's gently bubbling. Cook for 7 minutes, without a lid, stirring occasionally and making sure to scrape the bottom so the orzo does not stick. After 7 minutes the pasta should be almost tender (mixture will still be soupy). Add the bowl of sausage to the pot and stir through gently. Sprinkle on 3/4 cup Parmesan and stir to melt. Season again to taste -- the salt and pepper really pull all the flavors together.
SERVE: Consistency should be similar to risotto and very creamy. (Add a splash of milk if needed to thin consistency a bit.) Sprinkle remaining 1/4 cup Parmesan over individual plates. If desired, add some freshly chopped parsley and a squeeze of lemon to individual plates. Enjoy while hot.