Prepare the red dough. In a large mixing bowl, thoroughly combine the instant bread mix, active dry yeast, granulated sugar, and salt.
Measure the warm water and check its temperature with a thermometer. It should register between 105°F and 115°F so the yeast can activate properly without being exposed to excessive heat.
Pour the warm water and vegetable oil into the dry mixture. Add red food coloring in the desired quantity, then stir until the ingredients begin forming a shaggy dough.
Continue mixing only until no significant patches of dry ingredients remain. The dough should hold together, although it does not need to have a completely smooth texture at this point.
Shape the rolls and allow them to rise. Divide the prepared red dough into 12 equal portions. Shape each portion into a smooth ball.
Place the dough balls on a parchment-lined baking sheet, leaving approximately 2 inches of space between them to accommodate expansion.
Loosely cover the baking sheet with plastic wrap or a damp kitchen towel. Leave the dough at room temperature until the balls have approximately doubled in volume, usually 45 minutes to 1 hour depending on the warmth of the room.
A comfortably warm area of the kitchen, such as a location near a sunny window, may encourage a faster rise.
Make the black topping. While the red dough is rising, combine the active dry yeast, granulated sugar, vegetable oil, salt, and rice flour in a mixing bowl or mixer.
In a separate small bowl, blend the black food coloring or activated charcoal with enough additional water to produce a thick, paste-like mixture.
Add the colored liquid to the rice-flour mixture and stir thoroughly. The finished topping should be thick yet spreadable, with a consistency similar to cake batter.
Cover the black topping and allow it to stand for 15 minutes. This resting period gives the rice flour time to hydrate while allowing the dark color to intensify.
Coat the risen rolls. Once the red dough balls have doubled in size, generously spoon or spread the black mixture over their surfaces. The coating may be applied unevenly to create the characteristic rugged Halloween appearance.
Cover the coated rolls again with plastic wrap or a damp kitchen towel and leave them to rest for an additional 15 minutes. This brief final rise allows the yeast activity to continue and helps the topping settle onto the dough.
Bake the bread. Preheat the oven to the temperature directed on the instant bread-mix package.
Bake the coated rolls according to the package instructions, generally for about 20–25 minutes. The exposed red areas should be lightly golden and completely baked, while the dark topping should appear firm and slightly deeper in color.
Remove the baking sheet from the oven and allow the rolls to cool on the pan for several minutes. Transfer them to a wire cooling rack and leave them until completely cooled. The bread will continue to firm as its temperature decreases.
Serve. Once fully cooled, serve the Halloween Brimstone Bread as individual rolls. The contrasting red interior and black exterior create a dramatic presentation suitable for Halloween meals and gatherings.
Pair the rolls with soups or stews, or serve them as striking dinner breads as part of a Halloween-themed spread.