PREHEAT oven to 400°F. Microwave chocolate and butter in medium microwaveable bowl on MEDIUM 3 min. or until butter is melted. Stir until chocolate is completely melted; set aside.

BEAT eggs, granulated sugar and coffee in large bowl with electric mixer on medium speed until thickened. Add flour and the chocolate mixture; beat just until blended. Pour into 6 generously greased and lightly floured 6-oz. custard cups; place cups on baking sheet.

BAKE 11 to 15 min. or until cakes are puffed with crusted tops, but still soft in the centres. Cool 5 min. Invert cakes onto individual dessert plates. Sift icing sugar evenly over the cakes. Serve warm.