Use the largest bowl. Make the dressing in it and then add ingredients.
Whisk lemon juice, mustard (this may be in the lunch cooler), salt, and pepper in a large bowl . While whisking, slowly drizzle in oil until emulsified.
Break up lettuce leaves.
Cut avocados into cubes.
Add romaine, avocado, parmesan, almonds, salt, and pepper.
Toss to combine.