Preheat oven to 400 degrees F.

Trim greens from beets, reserving stems and greens. Place the beets in a baking pan, cover with foil and roast until very tender when pierced with a knife, 45 minutes to 1 1/2 hours, depending on the size of the beets. Uncover and let cool. Reduce oven temperature to 350 degrees F.

While the beets cool, arrange baguette slices in a single layer on a large baking sheet. Bake, turning the slices over once halfway through, until toasted but not browned, about 14 minutes.

Thinly slice the beet green stems and finely chop the leaves; keep stems and leaves separate. Heat 1 tablespoon oil in a large skillet over medium heat. Add the stems and cook, stirring occasionally, until tender, about 3 minutes. Add the remaining 1 tablespoon oil and garlic and cook, stirring, until fragrant, about 15 seconds. Add the greens, vinegar and water and cook, stirring occasionally, until the greens are tender and the liquid has evaporated, 4 to 5 minutes. Stir in salt and remove from the heat.

Peel the cooled beets and cut into 1-inch pieces. Place 3/4 cup beet pieces, goat cheese and pepper in a food processor and puree until smooth (reserve the remaining beets for another use).

To assemble crostini, spread about 2 teaspoons beet-cheese spread on each slice of toasted baguette and top with sauteed greens.

Tip: Look for bunches of beets with 2 to 3 medium-to-large beets for this recipe. If you have trouble finding beets with greens still attached, use loose beets plus 3 cups finely chopped chard greens and thinly sliced stems.

MAKE AHEAD TIP: Prepare through Step 4, store the beet spread and greens separately in the refrigerator for up to 2 days. Bring to room temperature before assembling.