Why It Works Roasting beets in foil concentrates their flavor while keeping them juicy and tender. Crème fraîche turns prepared horseradish into a cool, creamy heat that balances sweet roasted beets. Toasted pistachios contribute crunch, adding a nutty and textural contrast. I typically think of beets as a late-fall or winter vegetable, since they store very well after their growing season. But early to mid-summer is the best time to enjoy the sweetest, smallest beets of the year. Beets and horseradish are a classic Slavic/Jewish combination, and I think they work particularly well when those beets are roasted to enhance their sweetness and the horseradish comes in the form of a creamy sauce. I start by roasting beets using my  tried-and-true method : I form a pouch out of aluminum foil; place the beets inside with a little bit of oil, salt, and pepper (you can also add some herbs for extra aroma if you like); then seal it tight and throw it on a tray and into a 375°F (190°C) oven.…