Bake beets at 350 degrees for 45 minutes. Peel the roasted beets under running water. Cut into 1/2-inch cubes and set aside.
Boil the lentils in plenty of unsalted water until tender but not mushy, about 12 to 15 minutes. Drain in a colander over the sink. While still warm pour the lentils into a mixing bowl and toss gently with the olive oil and prune vinegar. Season with salt and lots of freshly-ground black pepper. Add the beet cubes to the lentils, stir to mix well and divide the beet and lentil mixture among 4 plates.
Toast or grill the bread slices until golden brown. Smear each slice of bread with about 2 ounces of taleggio cheese, place on top of lentil beet mixture and serve.
Source: MOLTO MARIO with Mario Batali From the TV FOOD NETWORK - (Show # MB-5622)