Spoon about 1½ teaspoons graham cracker crumbs into the bottom of each shot glass.
In a bowl, whisk together Splenda Sweetener and cornstarch. Whisk in egg substitute, vanilla, and salt until fully combined.
In a saucepan, combine milk and whipping cream; bring to a simmer. Remove from heat and slowly whisk into egg mixture. Return mixture to saucepan and simmer over low heat, whisking slowly until mixture is thick and smooth.
Remove from heat and stir in chocolate and margarine until smooth.
Immediately spoon chocolate mixture over graham cracker crumbs in each shot glass. Cover and refrigerate until set, about 20 minutes.
To serve, top each portion with 1 tablespoon marshmallow cream. Use a kitchen torch to lightly brown marshmallow cream. Sprinkle with remaining graham cracker crumbs.