Boil the lentils in a pot of water until they are done, yet still crisp, approximately 20-30 minutes. Do not overcook or they will be mushy. (Check frequently.)
Drain and rinse lentils, and set aside.
Heat oven to 450F degrees.
Peel and slice the sweet potatoes into ¼-inch rounds.
Place the sweet potato slices in a bowl and top with about 2 tablespoons olive oil.
Sprinkle with rosemary leaves, nutmeg, a tiny bit of salt and pepper.
Spread them evenly in a single layer on a jelly roll pan or cookie sheet that you have covered in parchment paper.
Roast potatoes in a 450-degree oven for 15-20 minutes.
Turn the slices over and roast for another 7-10 minutes. (Watch carefully so they don't burn.)
While potatoes are cooking, add a little water to the apple pieces and cook them in the microwave for about 3 minutes. Drain.
In a skillet on top of the stove, sauté the onions and garlic in a little olive oil until the flavors are enhanced; add the drained apples.
Dressing
Whisk together remaiing olive oil, lemon, salt, pepper and garlic until emulsified.
Put It Together
In a large bowl combine the lentils, sweet potatoes, apples and onions mixture.