For the mole negro: In a large saute pan over medium heat, toast the ancho and guajillo chiles on both sides until softened and fragrant, being careful not to scorch them, 20 to 30 seconds. Add 1 cup of hot water to the pan, just enough to cover the chiles, and set aside for 30 minutes to reconstitute. Add the chiles and soaking water to a blender. Then add the onions, almonds, raisins, piloncillo, sesame seeds, cinnamon, oregano, garlic, cloves and 1/2 cup of the chicken broth. Puree until very smooth, adding a little more chicken broth if too thick.
In a 6-quart Dutch oven over medium-high heat, add the lard and the mole puree and cook, stirring constantly, until most of the liquid has evaporated and the mixture becomes glossy, 6 to 8 minutes. Add the remaining 2 1/2 cups chicken broth and the chocolate. Boil for about 5 minutes, then reduce to a simmer and cook, uncovered, until thick, about 15 minutes. Add the salt; taste and adjust as needed. Remove from the heat, cover and keep warm.
For the grilled chicken: Preheat the oven to 350 degrees F. Prepare a grill for high heat and wipe down the grates with an oil-blotted paper towel.
Combine the granulated garlic, salt, ancho powder, cumin, chipotle powder, pepper and cayenne in a small bowl and mix well. Sprinkle the chicken pieces all over with spice mixture. Place the chicken on the grill, skin-side down, and cook until nicely charred, 3 to 4 minutes. Flip and cook on the reverse side for another 3 to 4 minutes. Once chicken has acquired nice grill marks, transfer it to a roasting pan and finish cooking in the oven, 15 to 20 minutes.
To serve, ladle the mole sauce onto a large platter and arrange the grilled chicken, skin-side up, on the top. Garnish with scallions and cilantro. Serve with extra mole sauce on the side.