PRE-HEAT OVEN TO 375o
TRIM OFF BEET GREENS AND ROOT ENDS, LEAVING ABOUT AN INCH ON BOTH ENDS OF THE BEETS.
LINE A CAST IRON SKILLET OR RIMMED BAKING SHEET WITH ALUMINUM FOIL. PLACE BEETS IN THE FOIL. SEASON WITH A DRIZZLE OF OLIVE OIL AND SALT. WRAP THE BEETS IN THE FOIL AND ROAST IN THE OVEN FOR 45 MINUTES TO AN HOUR, DEPENDING ON THEIR SIZE. REMOVE FROM THE OVEN WHEN THEY ARE PIERCED EASILY WITH A SHARP KNIFE.
DRIZZLE A FEW TBSPS OF SHERRY WINE VINEGAR OVER THE BEETS.
ONCE THE BEETS ARE COOL ENOUGH TO HANDLE, TRIM OFF THE ROOT END AND STEM. UNDER COLD WATER SCRAPE OFF THE OUTER SKIN. (IF YOU DON’T WANT TO STAIN YOUR HANDS, USE DISPOSABLE RUBBER GLOVES.)
WHILE THE BEETS ARE ROASTING, PEEL AND DICE THE ONION. SWEAT THE ONION IN 1 TBSP OF OLIVE OIL AND 1 TBSP OF BUTTER IN A LARGE COVERED SAUCEPAN OR DUTCH OVEN OVER A LOW FLAME. TRIM AND ROUGHLY CHOP THE GARLIC. ADD TO THE POT AND COOK ANOTHER MINUTE OR SO. STRIP THE LEAVES FROM THE THYME AND ADD IT AS WELL.
STIR IN 1 TBSP OF CONCENTRATED TOMATO PASTE. COOK ANOTHER MINUTE, STIRRING THE PASTE IN WITH THE ONIONS.
CHOP THE BEETS INTO LARGE CHUNKS AND ADD TO THE SAUCEPAN. STIR A MINUTE OR SO WITH THE ONIONS AND GARLIC, THEN ADD THE WINE. BOIL FOR A MINUTE, THEN FILL THE POT WITH WATER, COVERING THE BEETS BY 2 INCHES.
BRING TO A BOIL, REDUCE TO A SIMMER. SIMMER FOR 30 MINUTES PARTIALLY COVERED.
ALLOW THE BEETS TO COOL. PUREE AT HIGH SPEED IN A FOOD PROCESSOR UNTIL THE MIXTURE IS QUITE SMOOTH. YOU’LL NEED TO DO THIS IN BATCHES.
ADJUST SEASONING WITH SALT AND PEPPER. ADD ONE TSP OF SRIRACHA OR CHILI SAUCE. IF YOU LIKE IT SPICY, ADD MORE.
CHILL IN THE REFRIGERATOR FOR AT LEAST 2 HOURS BEFORE SERVING.
BEAT 1⁄2 CUP OF YOGURT IN A BOWL WITH A TBSP OF HEAVY CREAM.
LADLE THE SOUP INTO INDIVIDUAL CHILLED BOWLS. SWIRL IN SOME SOUR CREAM. GARNISH WITH CHOPPED CHIVES AND DILL.
SERVES 6