Arrange carrot in a vegetable steamer over boiling water. Cover; steam 2 to 3 minutes or until crisp-tender. Transfer carrot to a serving bowl, and keep warm.
Combine cornstarch and lemon juice in a small saucepan, stirring until smooth. Add water; cook over medium heat, stirring constantly, until thick.
Stir in butter and next 3 ingredients. Cook, stirring constantly, until butter melts.
To serve, pour lemon juice mixture over carrot, and toss gently.