Heat 2 tablespoons of the olive oil in a large deep skillet or heavy shallow, wide pot over medium heat. Sauté the onions and scallions in the oil until soft and glistening, about 8 minutes, stirring. Add the garlic and stir to soften, about 5 minutes.

Add the tomatoes, ouzo, star anise, and mustard. Stir to combine. Cook until the alcohol in the ouzo has burned off and most of the liquid let off from the tomatoes has evaporated, about 6 – 8 minutes.

Add the shrimp, raise the heat a bit and cook until the shrimp are bright pink and cooked, about 3 – 4 minutes. Add the olives and feta and cook all together for about a minute, or until the feta just begins to melt. Season to taste with salt, pepper, lemon zest, and hot pepper flakes and stir in the parsley. Remove the star anise.

Place a heavy skillet or griddle over medium-high heat on top of the stove. Brush the bread of your choice with the remaining olive oil and briefly warm on the open-faced side in the hot skillet. Fill each piece of bread with half the shrimp saganaki mixture and serve.