Put dry bulgur into a bowl and pour boiling water over it until water is 2 inches above bulgur. Let soak for about 45 minutes to one hour, or until bulgur has soaked up most of the water and is soft to the touch. Drain and squeeze in a cheesecloth or small hand towel to remove extra water.
Toss bulgur, parsley, onion, mint, and allspice in a large mixing bowl (add tomatoes and cucumber, if using). Drizzle with olive oil and lemon juice and stir to combine.
Prep Ahead: Make bulgur up to two days ahead of tabbouleh salad preparation
Leftovers and Storage: Store bulgur tabbouleh in an airtight container in the refrigerator for up to four days.
Nutrition notes: Nutrition information calculated without addition of tomatoes and cucumber. This vegan bulgur tabbouleh recipe contains whole grains and is high in healthy plant-based fats and dietary fiber per serving.