Preheat the oven to 425°F and cut the greens from the beets, leaving about ¼ inch of stem attached, then scrub them clean.

Place the beets in a baking dish with ¼ inch of water, cover tightly, and roast for 40 to 45 minutes until tender.

Allow the beets to cool, trim the ends, slip off the skins, and slice them crosswise into ¼-inch-thick rounds.

Heat the olive oil in a heavy saucepan over medium heat and cook the minced shallots for about 3 minutes until softened.

Stir in the sifted flour and cook for 3 minutes until smooth and bubbly without browning.

Whisk in the skim milk and half-and-half, bring to a simmer, and cook while whisking until thickened.

Reduce the heat to very low and simmer for 10 to 15 minutes, stirring often, until the sauce no longer tastes of raw flour.

Season the sauce with salt, pepper, and nutmeg, then strain while hot and stir in the chopped chives or parsley and ¼ cup Parmesan.

Reduce the oven temperature to 350°F and oil a rectangular baking dish.

Spread a small amount of béchamel in the dish and layer with lasagna noodles.

Add a thin layer of béchamel, a layer of beet slices, dots of ricotta, and a sprinkle of Parmesan.

Repeat the layers, ending with noodles topped with béchamel and Parmesan, ensuring all noodles are well coated.

Cover tightly with foil and bake for 40 minutes until bubbling and the noodles are tender.

Uncover and bake an additional 5 to 10 minutes if a lightly browned top is desired.

Let the lasagna rest for 5 minutes before slicing and serving.