4fresh poblano chiles, roasted, sweated, peeled, seeded, and cut into 1-x-1/4-inch strips
Heat the oil in a large saucepan over medium-high heat, until very hot but not smoking. Add the rice and cook, stirring often, until it starts to become milky white, crackles, and feels heavier as you stir it, 2 to 3 minutes.
Clear a space in the center of the pan and add the butter. Once it melts, add the onion and corn and cook, stirring and mixing with the rice, for 2 to 3 minutes, until the onion begins to soften. Add the salt and allspice, stir well, and stir in the broth or water. Bring to a boil, add the poblanos, stir once, cover, and reduce the heat to the lowest setting.
Simmer for 12 to 15 minutes, until most of the liquid has been absorbed but there is still some moisture in the pan. The rice should be tender; if it is not but all the liquid has been absorbed, add 2 tablespoons or so of broth or water, cover again, and cook for a couple more minutes.
Remove from the heat and let rest, covered, for 5 minutes. Fluff the rice with a fork, taste and adjust the salt, and serve.