Whisk the eggs together in a bowl, then add the brown sugar and mix well.
Place the milk and cream into a saucepan and bring to a gentle simmer. Remove from the heat and gradually pour onto the egg and sugar mixture, whisking constantly until well combined. Pour the mixture through a sieve into a large jug. Mix in vanilla.
Place four small cups or ramekins in a baking dish or wide shallow pan and fill them up with the custard mixture. Pour enough hot water into the baking dish to come halfway up the sides of the cups or ramekins and cover the ramekins with foil. Bake in the oven for 40-45 minutes, or until the custards are just set in the center.
Remove the custards from the baking dish and remove the foil. Serve warm or allow to cool. Sprinkle a little bit of extra brown sugar on top just before serving.
Recipe by Maya Kitchenette at https://mayakitchenette.com/5-ingredients-brown-sugar-custards/