Cook the pitted cherries with a few tablespoons of water on low heat until juices are released, about 10-15 minutes. Puree and strain.

Squeeze half a lemon into a bowl to extract the juice.

In a heatproof bowl, whisk the whole eggs, egg yolks, and sugar together until blended.

Heat the cherry puree with lemon juice over medium heat until it bubbles gently, then remove from heat.

Gradually mix the hot cherry puree into the egg mixture, stirring continuously.

Return combined mixture to pot and stir on low heat for 5-7 minutes until thickened.

Off the heat, add chopped unsalted butter and stir until fully melted.

Taste and adjust the sweetness or acidity as needed.

Pour into a clean container, cover, and refrigerate until cooled, about an hour.