Step 1

FOR THE TRI-TIP: Process coriander seeds and peppercorns in spice grinder until coarsely ground; transfer to small bowl. Stir in salt, sugar, and granulated garlic. Sprinkle tri-tip all over with spice mixture. Wrap tri-tip tightly in plastic wrap and refrigerate for 12 to 24 hours.

Step 2

FOR A CHARCOAL GRILL: Open bottom vent completely. Light large chimney starter half filled with charcoal briquettes (3 quarts). When top coals are partially covered with ash, pour into steeply banked pile against side of grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.

Step 3

FOR A GAS GRILL: Turn all burners to high; cover; and heat grill until hot, about 15 minutes. Leave primary burner on high and turn off other burner(s).

Step 4

Clean and oil cooking grate. Insert probe thermometer into thickest part of tri-tip. Place tri-tip directly over coals on charcoal grill or over primary burner on gas grill and cook until well-browned on both sides, 5 to 7 minutes per side. Transfer tri-tip to cooler side of grill. Cook, covered, until meat registers 125 degrees on charcoal grill, 20 to 30 minutes, or 130 degrees on gas grill, 30 to 40 minutes (target temperatures differ between charcoal and gas to account for differences in carryover cooking). Transfer tri-tip to carving board and tent with aluminum foil. Let rest for 10 minutes.

Step 5

FOR THE CILANTRO-LIME SAUCE: Meanwhile, bring cream, wine, shallot, and salt to boil in small saucepan over medium-high heat. Reduce heat to medium-low and simmer until mixture is reduced to scant ½ cup, 10 to 15 minutes. Let cool slightly (do not chill), about 15 minutes.

Step 6

Transfer cream mixture to blender. Add cilantro, jalapeños, lime zest and juice, and garlic and process until smooth, 1 to 2 minutes. Season with salt to taste. Slice tri-tip thin against grain. Serve with sauce.