Whisk egg yolks and sugar in heatproof bowl until pale yellow. Heat milk in saucepan over high heat to boiling. Slowly add to yolk mixture, whisking. Pour mixture back into saucepan. Cook over low heat, stirring, until mixture thickens and coats back of spoon, about 10 minutes; do not boil or mixture may curdle. Remove from heat. Stir in vanilla. Chill 1 hour.
Stack phyllo sheets. Cut stack lengthwise in fourths, then crosswise in fourths again for a total of 16 stacks (each stack consists of 4 individual pieces of phyllo). Keep phyllo covered with moist paper toweling to prevent drying out.
Heat oven to 375 degrees F.
Lightly coat 10-ounce custard cup with nonstick cooking spray. Take 1 stack of phyllo. Lightly coat each of the 4 sheets in a stack with nonstick cooking spray. Gently press stack into prepared cup, to one side. Repeat with 3 more stacks, coating with spray and placing at right angles, overhanging edge of cup. Bend overhangs upright. Repeat with 3 more custard cups. Place custard cups in jelly-roll pan.
Bake in 375 degree F oven for 10 to 12 minutes or until phyllo is crisp and golden. Cool in custard cups on rack.
Meanwhile, combine berries and sugar in large bowl. Let stand 20 minutes, stirring occasionally.
To serve, remove phyllo cups from custard cups to 4 plates. Spoon 2 tablespoons custard sauce evenly around each phyllo cup and 2 tablespoons into each cup. Spoon berries into cups. Drizzle with melted chocolate. Sprinkle with sugar; garnish with mint. Makes 4 servings.