• Place chicken on large plate and sprinkle both sides with 1 teaspoon salt and 1 teaspoon pepper.

  Toss shrimp with 1 tablespoon oil, ½ teaspoon garlic, ¼ teaspoon paprika, and ¼ teaspoon salt in bowl until evenly coated. Set aside.

For the "broth"

• Heat 1 tablespoon oil in medium saucepan over medium heat until shimmering.

  Add remaining garlic and cook, stirring constantly, until garlic sticks to bottom of saucepan and begins to brown, about 1 minute.

  Add tomato paste and remaining 1½ teaspoons paprika and continue to cook, stirring constantly, until dark brown bits form on bottom of saucepan, about 1 minute.

  Add broth, clam juice, sherry, and saffron, if using. Increase heat to high and bring to boil. Remove saucepan from heat and set aside.
• For a Charcoal Grill: Open bottom vent completely. Light large chimney starter mounded with charcoal briquettes (7 quarts).

  When top coals are partially covered with ash, pour evenly over grill. Using tongs, arrange 20 unlit briquettes evenly over coals.

  Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.
• For a Gas Grill: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Leave all burners on high.
• Clean and oil cooking grate. Place chicken on grill and cook until both sides are lightly browned, 5 to 7 minutes total. Return chicken to plate. Clean cooking grate.

Grilling instructions:

• Place roasting pan on grill (turning burners to medium-high if using gas) and add remaining ¼ cup oil.

  When oil begins to shimmer, add onion, red peppers, and ½ teaspoon salt.

  Cook, stirring frequently, until onion begins to brown, 4 to 7 minutes.

  Add rice (turning burners to medium if using gas) and stir until grains are well coated with oil.
• Arrange chicken around perimeter of pan.

  Pour broth mixture and any accumulated juices from chicken over rice.

  Smooth rice into even layer, making sure nothing sticks to sides of pan and no rice rests atop chicken.

  When liquid reaches gentle simmer, place shrimp in center of pan in single layer. NOTE: Since shrimp cooks quickly and overcooked shrimp turns tough, I waited to add the shrimp until the last 5 minutes of cooking the paella.)

  Arrange clams in center of pan, evenly distributing with shrimp (see note) and pushing hinge sides of clams into rice slightly so they stand up.

  Distribute chorizo evenly over surface of rice.

  Cook (covered if using gas), moving and rotating pan to maintain gentle simmer across entire surface of pan, until rice is almost cooked through, 12 to 18 minutes. (If using gas, heat can also be adjusted to maintain simmer.)
• Sprinkle peas evenly over paella, cover grill, and cook until liquid is fully absorbed and rice on bottom of pan sizzles, 5 to 8 minutes.

  Continue to cook, uncovered, checking bottom of pan frequently with metal spoon, until uniform golden-brown crust forms, 8 to 15 minutes longer. (Rotate and slide pan around grill as necessary to ensure even crust formation.)

  Remove pan from grill, cover with aluminum foil, and let stand for 10 minutes. Serve with lemon wedges.