Yes, you can toast aromatics like spices and dried chilies without oil for dry curries. This technique, called dry roasting, enhances their flavor and aroma by releasing essential oils.
Dry roasting involves heating spices and other aromatics in a dry pan over medium-low heat. The absence of oil allows for a more controlled and even toasting process, preventing burning. As the aromatics heat up, their volatile compounds are released, intensifying their flavor profile. This method is particularly beneficial for dry curries because it creates a deeper, more complex flavor base without adding extra fat. The heat helps to unlock the flavors that would otherwise remain dormant. Common aromatics that benefit from dry roasting include cumin seeds, coriander seeds, dried chilies, peppercorns, and cloves. The process typically takes only a few minutes, and it's crucial to monitor the aromatics closely to prevent them from burning, which can impart a bitter taste. Once toasted, the aromatics can be ground into a powder or used whole, depending on the recipe.
Toast spices in small batches to ensure even heating and prevent burning. A heavy-bottomed pan works best for distributing heat evenly.