This will be your starting position.
One of the greatest muscle density building programs that was created and is still being used widely today is the 5X5 Program.
Because of the fixed bar path it allows you to push as much weight as possible without having to worry about stabilizing the load.
Lunges are right up there with squats on the list of best exercises you can do.
Obviously, it's best to train your weakest leg first when you're at your freshest and strongest.
Extend through the hips and knees.