Soak the cashews in boiling water for 15 minutes and then blend with tofu, lemon zest, lemon juice, and salt until smooth.

Chop the red onions and combine with olive oil, vinegar, lemon juice, sumac, salt, and parsley; marinate for 10-15 minutes.

Slice heirloom tomatoes and mix with olive oil, garlic, parsley, basil, and lemon juice. Let sit for 5-10 minutes.

Spread creamy tofu on a slice of bread, add mashed avocado, marinated tomatoes, and sumac onions. Top with another slice of bread.

Cut the sandwich in half and drizzle any leftover marinade before serving.