Coat the peppers with vegetable oil and place them on a sheet pan. Use a propane torch to blacken the skin, turning the peppers to cook all sides. If you are making more than a single recipe, bake the peppers at 450°F(230°C) until blackened, turning them once or twice. Wrap the peppers in a moist towel or place them in a plastic bag and set aside to cool to room temperature.
Peel the peppers and remove the seeds and stems. Puree the roasted pepper flesh in a food processor then force the puree through a fine strainer.
Stir the powdered sugar and flour into the puree.
Spread the batter out thinly and evenly on Silpats in freeform shapes, approximately 2 × 3 inches (5 × 7.5 cm) each.
Bake at 200° to 250°F(94° to 108°C) until the decorations are dry and have started to brown slightly at the edges. Use a thin spatula to remove them from the Silpat as soon as possible and place the decorations on a flat surface to cool; be very careful, they are quite fragile. If desired, the warm decorations can be molded in the same way as tuile paste. Store in airtight containers.