Heat oven to 400°F.
In top of double boiler, melt chocolate and 1/2 cup butter over simmering water, whisking.
In medium-size bowl, whisk eggs, sugar and 1/4 cup flour just until blended. Gradually whisk in melted chocolate mixture; set aside.
Grease four 1-cup ramekins with 1 tablespoon butter. Coat with 1 tablespoon flour; shake out excess. Divide chocolate mixture among ramekins. Place on baking sheet.
Bake in 400°F oven 18 minutes, until tops are firm and cracking slightly and edges are set. Serve immediately. If desired, serve with cold cream to pour into hot puddings.