Lentil Bacon Salad

1 cup brown lentils
3 slices bacon, chopped
1/2 medium red onion, diced small
1 stalk celery, diced small
1/2 cup fresh parsley, chopped 
2 tablespoons red-wine vinegar 
2 teaspoons Dijon mustard 
2 tablespoons extra virgin olive oil 
Sea salt and ground pepper to taste

1. Bring lentils and 4 cups water to a boil. Reduce heat and cook until lentils are tender but not mushy, about 20 minutes. During the last 5 minutes of cooking stir in a generous sprinkling of salt. Drain well and let cool. 
2. Cook bacon until crisp, about 8 minutes. Transfer to a paper-towel-lined plate to drain.  
3. In a medium bowl, whisk together the vinegar, mustard, oil, salt and pepper. Add lentils, onion, celery, parsley and bacon and toss to coat.