Preheat your oven to 180°C (356°F) and lightly grease your baking dish.
Cook the pasta in salted boiling water until just al dente, about 2 minutes less than package instructions, then drain well.
While the pasta cooks, heat olive oil in a skillet over medium heat. Add chopped onion and cook until translucent and fragrant, about 5 minutes.
Add minced garlic to the skillet and cook for another minute until fragrant, stirring constantly.
Stir in plant-based milk, nutritional yeast, and lemon juice, then season with salt and pepper. Let the mixture simmer gently for about 5 minutes until slightly thickened and fragrant.
Mix the cooked pasta into the skillet, tossing gently to coat every piece with the sauce.
Transfer the coated pasta to your prepared baking dish, spreading it out evenly.
Sprinkle your choice of plant-based cheese or breadcrumbs evenly over the top for a crispy, golden finish.
Bake uncovered for 20-25 minutes until bubbly and the top is golden brown.
Remove from the oven and let rest for 5 minutes; this helps the dish set and makes serving easier.
Garnish with fresh herbs if desired, then serve hot and enjoy the rich, cheesy flavor and satisfying texture.