Sardella is a savory Calabrian-style red spread, slicked with olive oil and packed with that irresistible tinned-fish depth, meant to be spooned generously over bread, potatoes, or grilled vegetables.
Place the potatoes in a large pot and cover with cold, well-salted water. Set over high heat and bring to a boil. Cook until the potatoes are tender but not falling apart. Drain and set aside.
Meanwhile, preheat the oven to 425°F (220°C).
Arrange the drained potatoes on a baking sheet. Gently smash each potato with the bottom of a glass, drizzle generously with olive oil, season with salt and pepper, and transfer to the oven. Roast for 30 to 40 minutes, turning once halfway through, until golden and crisp on both sides.
While the potatoes roast, prepare the sardella. Add the bell peppers, onion, garlic, sardines, anchovies (with their oil), and red chili flakes to a blender. Blend until completely smooth.
Heat the olive oil in a wide skillet over medium heat. Add the tomato paste and cook, stirring, for about 5 minutes, until it darkens slightly and smells sweet and toasted.
Carefully add the blended mixture to the skillet. Cook over medium-low heat, stirring often, for 10 to 15 minutes, until thick, glossy, and concentrated. Add more olive oil if needed. Taste and adjust salt.
Serve the sardella warm or at room temperature alongside the crispy smashed potatoes.