For the sofrito: Heat the 2 tablespoons olive oil in a medium saute pan over medium heat for 1 minute, and then add the celery, garlic, fennel and onions. Sprinkle with salt and pepper and cook until the onions are transparent and the celery has softened, 10 minutes. Spoon the mixture into a blender and add the bacon or pork. Puree the mixture, simultaneously drizzling in the extra-virgin olive oil. Set aside.

For the shrimp toast: Put the shrimp, 1/2 teaspoon sesame oil, onion, cilantro, salt, cayenne, avocado and egg white into a food processor and pulse 2 or 3 times to finely chop. Do not puree. Put the egg yolks, remaining 2 tablespoons sesame oil and 1/4 cup water in a shallow bowl and whisk to blend. Spread equal amounts of the shrimp mixture onto 8 slices of the bread. Top with the remaining 8 slices of bread. Press together gently but firmly. Heat 3 tablespoons of the vegetable oil in a large nonstick skillet over medium-high heat. Dip 4 of the sandwiches in the egg mixture, coating them evenly on both sides. Fry until golden brown, about 4 minutes per side. Remove from the skillet. Repeat the process with the remaining 3 tablespoons vegetable oil and sandwiches. Slice each sandwich into 4 triangles to serve. Keep warm.

For the grouper: Preheat a large, nonstick skillet over medium-high heat. Sprinkle the grouper with salt and black pepper. Add the olive oil to the skillet. Carefully add the grouper to the hot pan without overcrowding. Cook until well-seared and cooked through, 3 minutes per side. Remove from the skillet.

For assembly: Ladle the sofrito into 4 shallow bowls. Place one grouper fillet on top in each bowl, and then arrange four triangles (one quartered sandwich) of shrimp toast around the grouper and sofrito. Serve any extra shrimp toast on the side.