Ingredients

• 1 lb. firm white skinless fish fillets (such as mahi-mahi, cod, or halibut), cut into 2" pieces
• Kosher salt, freshly ground pepper
• 1 Tbsp. fresh lemon juice
• 1 Tbsp. red wine vinegar
• 1/2 tsp. Dijon mustard
• 3 Tbsp. extra-virgin olive oil, divided
• 1 cup dry or instant polenta (coarse cornmeal)
• 1 garlic clove, smashed
• 1 medium yellow bell pepper, seeds and ribs removed, cut into 2" pieces
• 1 medium zucchini, cut into 2" pieces
• 1 pint cherry or grape tomatoes, halved
• 1 Tbsp. slivered fresh basil (or 1 tsp. dried), plus whole leaves for serving
• 1 tsp. chopped fresh oregano (or 1/2 tsp. dried), plus whole leaves for serving

Instructions

1. Season fish with salt and pepper. Whisk lemon juice, vinegar, mustard, and 2 Tbsp. oil in a medium bowl. Add fish, toss to coat, and chill until ready to use.
2. Cook polenta according to package directions.
3. Meanwhile, heat remaining 1 Tbsp. oil in a large skillet over medium-high. Cook garlic, stirring occasionally, until beginning to brown, about 2 minutes. Transfer garlic to a plate.
4. Cook bell pepper in same skillet, stirring frequently, until beginning to brown and soften, about 3 minutes. Add zucchini, cover, and cook 3 minutes.
5. Reduce heat to medium-low. Add tomatoes, garlic, fish and dressing, 1 Tbsp. slivered basil, and 1 tsp. chopped oregano; season with salt and pepper. Cover and simmer just until fish is cooked through, about 5 minutes. Discard garlic, if desired.
6. Divide polenta among bowls. Arrange fish mixture over. Garnish with basil and oregano.