Preparation

• Position a rack in the center of the oven, and heat the broiler on high. Melt the butter in a large oven-safe skillet, preferably cast iron, over medium heat until it starts foaming. Stir in the leeks along with a big pinch of salt, then cover the pan and allow the leeks to soften for 5 minutes. Add the bell pepper, chard, and garlic, and cook, stirring occasionally, until the pepper and chard soften and the garlic is fragrant, about 4 minutes. Turn off the heat.
• Meanwhile, put the gnocchi in a deep heatproof bowl. Pour in enough boiling water (about 5 cups) to cover the gnocchi, and let stand for 2 minutes. Drain well. Add the gnocchi to the pepper-chard mixture. Stir in the heavy cream, and then season to taste with salt and pepper. Crumble and scatter the goat cheese evenly on top. Sprinkle the panko over the top, and drizzle with the oil.
• Transfer the skillet to the broiler, and broil until the breadcrumbs are crisp and golden brown, 3 to 5 minutes, watching closely to prevent burning. Serve immediately.