Prepare udon noodles as directed on package. Drain and rinse under cold water. Set aside.
Combine softened butter and minced garlic in a small bowl, set aside.
In a large skillet heat 1 Tbsp of vegetable oil over medium high heat. Add shrimp and sauté one minute per side. Add garlic butter and lemon juice, sauté for one more minute until butter melts and shrimp is pink, ant then remove into a bowl and set aside.
Add remaining 1 Tbsp of vegetable oil to skillet and then add the mushrooms, zucchini and green onions. Saute for 5-7 minutes, until vegetables begin to carmelize.
Put shrimp and udon noodles back in skillet with vegetables, and add chicken stock, soy sauce and sesame oil. Toss with tongs to combine. Serve warm with optional toppings (hot sauce, sesame seeds).