Cook udon noodles according to package instructions. Reserve 1/2 cup of the cooking water, then drain.
Season shrimp with salt and pepper.
Heat a drizzle of oil in a pan over medium heat. Cook shrimp 1–2 minutes per side until just cooked through. Remove and set aside.
In the same pan, melt butter and add garlic. Sauté until fragrant.
Stir in soy sauce, gochujang, and heavy cream until smooth.
Add udon noodles and reserved cooking water. Toss until the sauce thickens and coats the noodles.
Return shrimp to the pan and toss to combine.
Garnish with parsley and serve warm.