Preheat the oven to 400 degrees. In a saute pan, heat 2 tablespoons olive oil. Caramelize the onions for 2 to 3 minutes. Remove from the heat and turn into the mixing bowl of an electric mixer. Whisk in the milk, water, yeast, sugar and butter. Combine the flour, cilantro, and salt together. Add the flour to the milk mixture. Using a dough hook, mix the dough on low until slightly incorporated. Increase the speed and continue mixing until the dough starts to crawl up the dough hook and comes away from the side. Place the dough in an oiled bowl, cover with plastic wrap, and place in a warm area. Let the dough rise until double in size, about an hour.
Turn the dough out into a floured surface and scale the dough into 8 4-ounce buns. Place the buns on a parchment-lined baking sheet and allow to rise until double in size. Egg wash the buns and sprinkle with sesame seeds. Bake for 10 minutes and then reduce the heat to 350 degrees. Continue baking for about 15 minutes or until the bread is done. Remove from the oven. Slice the buns in half. Season the tuna steaks with Essence. In a saute pan, heat 2 tablespoons olive oil. When the oil is hot, sear the tuna for 2 to 3 minutes on each side for rare. Remove from the heat.
Yield: Dough: 8 buns