Lightly butter eight 8-ounce ramekins or 1-cup souffle dishes; line bottoms with parchment or wax paper. Place the prepared ramekins on a shallow baking pan or on a large cookie sheet. Set aside.
In a heavy-bottomed, medium saucepan, melt butter and chocolate over low heat, stirring constantly. Remove from heat; cool slightly. (Or, in a mixing bowl, combine the butter and chocolate. Place mixing bowl over a pot of simmering water and melt butter and chocolate, stirring occasionally. Remove bowl from the simmering water pot; set aside to cool slightly.)
In a large mixing bowl, beat eggs and egg yolks with an electric mixer on high speed for 5 minutes or until thick and lemon-colored. Mix a large dollop of the beaten eggs into the butter-chocolate mixture. Gently fold until combined. Add butter-chocolate mixture to remaining beaten egg mixture and fold. After a few folds, sprinkle in sugar, flour, vanilla, and salt. Continue to fold until the mixture is combined.
Quickly divide the batter evenly among prepared ramekins. Bake in a 350 degree F oven for 9 to 10 minutes or until cakes feel firm to the touch on top edges, but still soft in the center when pressed with a fingertip. Remove from oven; set ramekins on a wire rack. Let cakes cool completely in ramekins.
Line a baking sheet with parchment paper. When cakes are cool, use a small metal spatula to loosen edge of cakes from side of ramekin and unmold onto the parchment-lined baking sheet. The centers of the cakes are supposed to be soft. (If not using immediately, wrap in plastic wrap. Refrigerate until ready to use.)
When ready to serve, place cakes on a microwaveable serving plate. Heat in a microwave oven on 100 percent power for 1-1/2 to 2 minutes or until warm. (Center of cake will slightly pop up.) Serve with whipped cream and garnish with a splash of Raspberry Sauce and/or fresh raspberries, if you like. Makes 8 servings.
In a blender container or food processor bowl, cover and blend or process one 10-ounce package frozen and thawed red raspberries in syrup until pureed. Use a fine sieve to sieve berry mixture. Cover and refrigerate the sauce till ready to use. Makes 2/3 cup.