Heat the olive oil in a large, deep skillet over medium heat. Add the onion and stir until soft, about 5 minutes. Stir in the garlic, giving it a twirl in the pan to soften.

Add the rice to the skillet and stir until it is well-coated and glistening with olive oil and melted butter. Add one cup of the simmering broth, which should be in a pot within easy reach of the skillet. Keep stirring gently until the rice absorbs the broth. Add the ouzo and stir until absorbed and the alcohol has cooked off, for a minute or two. Add the tomato and star anise, stirring gently until the mixture is thick.

Add most of the remaining broth in increments of one cup, stirring, until the rice absorbs it and is creamy but al dente. Toss in the feta and stir until it melts. Add the oregano and lemon zest and stir to combine. Season at the end to taste with salt and pepper. Remove, stir in the tablespoon of butter, and serve immediately.