Wrap the beets together in foil and seal tightly. Place on a cookie sheet and cook in the oven for about 1 hour, or until a paring knife or skewer, when inserted into the center of the largest beet, meets no resistance. Remove beets from the oven and allow to cool.
When the beets are cool enough to handle, remove the skin with your fingers, a cloth, or paring knife. Cut beets into quarters and place in a high-speed blender or food processor. Add the lemon juice, tahini, and garlic. Blend until smooth, scraping sides as necessary. Add the olive oil, and blend to incorporate. Season to taste with salt. Set-aside.
For the Excellent Basic Crostini: Reduce the oven to 350°F.
Slice the baguette on the diagonal into ⅓ inch (approximately). Place slices on a cookie sheet and into the oven for 5 minutes, turn and continue for 3 - 5 minutes more or until they are golden and crisp.
Layer the beet puree over the crostini and top with goat cheese, OR layer the goat cheese on the crostini and top with beet puree. Sprinkle chopped pistachio over.
Make them the BEST: Drizzle with blood orange extra virgin olive oil if you want to take them over the top.