Prepare Marinade: In a large mixing bowl, whisk together the vegan yogurt, Dijon mustard, agave, lemon zest and juice, olive oil, soy sauce, minced garlic, nutritional yeast, and your choice of spices until smooth. Reserve 2 tablespoons of the marinade for later use.

Prepare Tofu: Pat the super firm tofu dry with a kitchen towel. Cut the tofu into bite-sized chunks.

Marinate Tofu: Coat the tofu pieces in the marinade, ensuring all sides are covered. Let it marinate for at least 15 minutes.

Cook Tofu: Thread the marinated tofu onto skewers. Preheat a non-stick skillet or grill pan over medium heat with a drizzle of olive oil. Cook the tofu for about 3 minutes per side.

Finish & Serve: Toss the cooked tofu in the reserved marinade. Serve in warm pita bread topped with homemade vegan tzatziki.