Heat your grill pan or the outdoor grill. You can also use a regular flat skillet, cast iron pan, or use a panini press. Once hot, brush the grill pan with oil then place the sliced vegetables on the pan. Brush some oil on the veggies. Sprinkle a little bit of salt and pepper and cook, pressing the veggies occasionally. You can use a spatula to press these vegetables down or use heavy grill weight. You can use skewers or toothpicks to keep the onion together.
Cook until the vegetables have good golden brown stripes on them. Flip and continue to cook. Place tofu slices on the grill as well. Brush with oil. Sprinkle with salt and pepper. Optionally, drizzle a few drops of soy sauce and grill on both sides.
Add all of the spread ingredients to the blender and a ¼ cup of water and blend.
Let the mixture sit for 2 to 3 minutes, then blend again and then add water, 1 tablespoon at a time, until the mixture is a spreadable consistency. Taste and adjust salt and flavor. This spread benefits from sitting for a bit. So make ahead and refrigerate for a few hours, if possible, and then adjust flavor if needed.
Toast your bread slices, then apply the spread on both of the slices. Top with the grilled vegetables, then close the sandwich and serve! You can also add some crunch with lettuce or sliced cucumber.
