Melt butter in a skillet over medium-low heat.
Sauté chopped onions in butter until lightly browned. Dredge lobster with flour and add to onions. Cook, stirring, for 3 to 5 minutes. Add sour cream and simmer for 15 minutes. Taste and adjust seasoning; serve on cornbread or toast. Lobster with sour cream serves 4.