Step 1

Preheat the oven to 400°F. Trim all but 1 inch of the beet stems. Put the beets on a large piece of aluminum foil, drizzle with olive oil, and seal the foil to make a tight package. Put the package in a small roasting pan. Roast the beets until easily pierced with a knife, about 1 hour. When the beets are cool enough to handle, peel them. The skins should slide right off with a bit of pressure from your fingers. If they don't, use a paring knife to scrape off any bits that stick. Dice the beets and set aside.

Step 2

While you roast the beets, spread the lentils on a pan and pick out any pebbles or other foreign matter; rinse and drain. Put the lentils in a saucepan with cold water to cover by about 2 inches. Add 1 teaspoon chopped rosemary and the bay leaf to the pan, along with the smashed garlic, onion, and ½ teaspoon salt. Bring to a boil over high heat; reduce the heat and simmer, uncovered, until the lentils are tender, about 25 minutes. Strain the lentils and discard garlic and onion.

Step 3

While the lentils are simmering, prepare the salad dressing: Whisk vinegar with mustard, salt and pepper in a small bowl. Gradually whisk in the olive oil, starting with a few drops and then adding the rest in a steady stream to make a smooth, slightly thick vinaigrette. Stir in the shallots. Use immediately or refrigerate in a tightly sealed container for up to 3 days.

Step 4

Put the warm lentils in a bowl and stir in half of the dressing. Cool the lentils completely, then add the beets, parsley, and remaining 1 teaspoon chopped rosemary. Season to taste with salt and pepper. Lightly dress the greens with a bit of the dressing and divide among 6 plates. Spoon some of the lentil salad onto the greens, crumble goat cheese over each serving, and drizzle with some of the remaining vinaigrette.