For a good supply:
3/4 cup lemon juice
1/2 cup white vinegar
2 toes garlic, minced
1 1/2 cups extra virgin olive oil
1/2 cup canola oil
In blender or processor, mince garlic. Drizzle in lemon juice and vinegar. Drizzle in oils. Add 1 tsp salt and a bit of black pepper...maybe 1/2 tsp.
Toss with romaine lettuce. Can add grated parmesan cheese to taste. Will keep 7-10 days in fridge.