Melt the butter in a medium saute pan. Add the radishes and toss to coat. Cook over medium heat for about 10 minutes, stirring occasionally until softened and golden brown. Remove from heat and add the lemon zest and chives. Season with salt and pepper to taste. Alternatively you could roast these in olive oil in a 375 degree (F) oven for about 35 minutes. Then add whatever seasonings you prefer.