Heat olive oil in a large Dutch oven over medium heat. Add onions and cook for 8-10 minutes until softened and starting to caramelize.
Add garlic and bell peppers, cooking for another 3 minutes until fragrant.
Layer the potato slices over the vegetables, then pour in the crushed tomatoes, white wine, and fish stock.
Add smoked paprika, saffron threads, and bay leaves. Season with salt and pepper, then bring to a boil.
Reduce heat to medium-low, cover, and simmer for 20 minutes until potatoes are tender.
Gently nestle the fish chunks into the stew, cover, and cook for 5 minutes.
Add the shrimp, cover again, and cook for another 3-4 minutes until shrimp are pink and fish is cooked through.
Remove bay leaves, taste and adjust seasonings. Garnish with fresh parsley and serve with crusty bread, or refrigerate overnight for even better flavor the next day.