Melt butter in heavy large saucepan over medium heat. Add shallots and saffron and cook 3 minutes, stirring occasionally. Add rice and stir to coat. Add stock and lemon juice; bring to boil. Reduce heat to low, stir and cover. Let simmer until creamy and tender, stirring vigorously every 10 minutes, 20 to 25 minutes. Add lemon peel and chives. Season with salt and pepper. Stir vigorously until well combined.