In a microwave-safe cup or mug, melt the butter for 10-20 seconds, or until fully melted.

Crush the digestive biscuits or graham crackers using either a food processor or in a ziploc bag with a rolling pin. Add the butter to the crumbs, divide evenly into two microwave safe jars (or ramekins) and press into the bottom. I found this easier using the bottom of a extract bottle for slim mouthed jars.

In another medium bowl, add the eggs, vanilla extract, cream cheese, sour cream, sugar, salt, and cornflour (cornstarch). Whisk gently until smooth then spoon or pour the mixture evenly into both jars.

Cook in the microwave for 30 second bursts, alternating between jars, for 1 minute 30 seconds. For example, pop first jar in microwave for 30 seconds, remove then pop the second jar in for 30 seconds, then return back to the first jar again and repeating for 3x 30 second bursts between jars.

Once cooked, allow to cool to room temperature before topping with the lemon curd. Chill in the refrigerator for at least 1 hour to chill.

Serve chilled. If desired, top with a little lemon zest.