Before beginning, fill a large bowl with ice water. Place a smaller bowl inside the ice bath. This will be used to cool the custard when it is finished cooking.

Place milk in a small saucepan and bring to a boil. Meanwhile, in a separate saucepan, combine yolks, sugar and cornflour and whisk over a low heat.

When the milk begins to boil, add a few tablespoons into the yolk mixture and whisk. Gradually add the remaining milk to the yolk mixture and whisk vigorously over medium heat. Custard will thicken. Continue to whisk until boils, and remove from heat. Scrape the custard into the small bowl over the ice bath to stop the cooking process. When the custard is slightly cooled, add the butter in 3-4 installments, stirring until combined. Add essence, mix and pour into one bowl or 4 small ramekins (I used 4 oz. mason jars). Refrigerate for up to 2-3 days.

Serve with jam, for topping (I have yet to taste a jam flavor that doesn't go beautifully with this dessert).