Cook macaroni until al dente; drain and set aside.
Heat olive oil in skillet; sauté vegan lobster and garlic for 5 minutes.
In saucepan, melt vegan butter; whisk in flour to make roux.
Gradually add plant milk, whisking until smooth.
Stir in Gruyère substitute, nutritional yeast, mustard, lemon juice, salt, and pepper until sauce is creamy.
Combine pasta, lobster, and sauce in baking dish.
Sprinkle breadcrumbs evenly on top.
Bake at 375°F (190°C) for 20 minutes, until bubbly and golden.
Garnish with parsley before serving.
