In a medium pot, combine the lentils, onion, carrot, garlic, bay leaf, and enough water to cover by 2 inches. Bring to a boil. Reduce the heat and simmer, partially covered, until the lentils are tender, about 30 minutes.
Drain; discard the onion, carrot, garlic, and bay leaf.
In a small frying pan, toast the pecans over moderately low heat, stirring frequently, until golden brown, about 5 minutes. Or toast them in a 350 oven for 5 to 10 minutes. Chop them.
In a large glass or stainless-steel bowl, whisk together 2 tablespoons of the vinegar, 1/2 teaspoon of the salt, and 1/4 teaspoon of the pepper.
Add the oil slowly, whisking.
Shred half the spinach and put in a large glass or stainless-steel bowl.
Add the hot lentils and toss with half the dressing, the remaining 2 tablespoons vinegar, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Toss the mixture gently until the spinach wilts.
Toss the remaining spinach into the remaining dressing and put on plates. Top with the lentil mixture and the toasted pecans. Using a vegetable peeler, shave the cheese over the top.
Wine Recommendation: This salad, with its lentils and rich cheddar, can easily stand up to a fruity red wine. A petite sirah's roasted-berry flavors make it just right for the part.
