1. In a medium saucepan, combine the milk and sugar. Heat over medium heat, stirring occasionally, until the sugar dissolves.
2. In a small bowl, mix the cornstarch with a few tablespoons of cold water until smooth, then slowly whisk it into the milk mixture. Cook, stirring constantly, until the mixture thickens, about 10-12 minutes.
3. Once thickened, remove from heat and stir in the rose water. Pour the mixture into serving bowls and let them cool to room temperature before chilling in the refrigerator for at least 2 hours.
4. In another saucepan, combine the cherries, honey, and lemon juice. Cook over medium heat until the cherries release their juices and the mixture thickens slightly, about 5-7 minutes. Let it cool completely.
5. Once the muhallebi is set, top each bowl with the cherry mixture and a sprinkle of pistachios if using.

Cooking tip: If your muhallebi feels a bit too thick, don’t panic! A splash of milk and a good whisk can bring it back to the creamy consistency you desire.