Sweet and Sour Mexican Style Fish

Name: Sweet and Sour Mexican Style Fish
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: Mexican
Ingredients: 4 tablespoons olive oil (divided); 1 cup white onion (slivered ); 4 garlic cloves (finely chopped); 1 pound ripe Roma tomatoes (diced); 1 pound tomatillos (husked and rinsed, diced); 1 teaspoon kosher or coarse sea salt (plus more to season fish); 1 teaspoon brown sugar; 1/4 teaspoon ground allspice; 1/4 teaspoon Ground ceylon cinnamon or canela; 1/4 cup slivered almonds; 1/4 cup sliced manzanilla olives stuffed with pimientos; 2 pounds halibut filet (skin on, cut into 6 pieces)