Using two kinds of parsley -- flat-leaf and curly-leaf -- brings a variety of textures to this salad. But it's also fine to choose just one, as long as you have two cups total.
Whisk together oil and lemon juice in a medium bowl, and season with salt and pepper. Add flat-leaf parsley, curly-leaf parsley, mint, and lettuce; toss to combine. Garnish with cheese.