Serves four (ideal for a 13- or 14-inch paella pan)
1/3 pound shrimp, peeled 3 cups chicken stock; more if necessary Pinch of saffron threads, toasted and steeped in 1/2 cup hot stock Salt to taste 1/4 cup extra-virgin olive oil 4 skinless chicken thighs, chopped in halves and seasoned with salt and pepper 1 red pepper, cored, seeded, and cut in 1-inch wide strips 1 small whole head garlic; plus 6 medium garlic cloves, peeled 2 marinated artichoke hearts 1/2 medium onion, grated on the largest holes of a box grater 1 ripe tomato, halved horizontally and grated on the largest holes of a box grater (discard the skin) 1 1/2 cups medium grain rice 8 small mussels or clams (1/2 pound), scrubbed 1 lemon, cut in wedges for garnish
1 In a saucepan, bring the stock to a boil; lower to a simmer. Add the saffron-infused liquid. Taste; the stock should be well-seasoned, so add salt if necessary. Remove from heat until ready to add to the rice.
2 Set a paella pan (14-inch diameter) over medium high heat with the olive oil, noticing if the pan sits level. If not, choose another burner or try to create a level surface. When the oil is hot, sauté the shrimp until almost cooked through, about 2 min. Transfer to a plate and set aside. Sauté the chicken pieces until golden and cooked through, 10 to 15 min. Transfer the chicken to a platter and set aside.
3 Reduce the heat to medium low. In the paella pan, sauté the red pepper, head of garlic, and garlic cloves until the peppers are quite soft but not brown, 15 to 20 min. Transfer the peppers and garlic cloves to a plate (the intact head always stays in the pan), cover with aluminum foil, and set aside to cool. Peel the peppers, and set the garlic cloves apart from the peeled peppers.
4 If there is more than 1 Tablespoon of olive oil in the pan, pour out the excess. Increase the heat to medium and sauté the onion until soft, about 5 min. Add the tomato and the reserved garlic to the pan. Season well with salt, and sauté until the water from the tomato has cooked out and the mixture has darkened to a burgundy color and is a very thick purée, 10 to 15 min. If not cooking the rice immediately, remove the paella pan from the heat. (This tomato-onion-garlic mixture, called the sofrito, is the flavor base for the paella.) You may make the paella several hours ahead up to this point.
5 About a half hour before you're ready to eat, bring the stock back to a simmer and set the pan with the sofrito over your largest burner (or over two burners) on medium high heat. When the sofrito is hot, add the rice, stirring until it's translucent, 1 to 2 min.
6 Stir or shake the pan to evenly distribute the rice, push the head of garlic to the center, and pour in the simmering stock. As the stock comes to a boil, lay the peppers in the pan, star-fashion. Add the artichokes, cut into halves and chicken pieces. Arrange the mussels or clams in the pan, submerging them as much as possible below the level of the liquid. Do not stir the rice once the water is boiling. Cook on medium high, rotating and moving the pan over one and two burners to distribute the heat and cook the rice as evenly as possible. When the rice begins to appear above the liquid, after 8 to 10 min., reduce the heat to medium low.
7 Continue to simmer, rotating the pan as necessary, until the liquid has been absorbed, about 10 min. more. Taste a grain just below the top layer of rice; it should be al dente, with a tiny white dot in the center. (If the rice is not done but all the liquid has been absorbed, add a bit more hot stock or water to the pan and cook a few minutes more.)
8 Arrange the shrimp in the pan. Cover the pan with aluminum foil and cook gently for another 2 min. to help ensure that the top layer of rice is evenly cooked. With the foil still in place, increase the heat to medium-high and, rotating the pan, cook for about 2 min., until the bottom layer of rice starts to caramelize, creating the socarrat. The rice may crackle somewhat, but if it starts burning, remove the pan from the heat immediately.
9 Let the paella rest off the heat, still covered, for 5 min. Sit everyone down at a round or square table. Remove the foil and invite people to eat directly from the pan, starting at the perimeter, working toward the center, and squeezing lemon over their section, if they want.