• Separate 4 eggs, putting the yolks into a large bowl.
• Add the caster sugar (30g) and whisk until combined.
• Add the plain flour (30g) and vanilla extract (½ tsp) and whisk until combined.
• Heat the full fat milk (300ml) on a very gentle heat until warmed but not quite boiling. Stir regularly to ensure that it does not burn.
• Once the milk is warm, remove from the heat and gradually add to the large bowl a bit at a time. Whisking each addition in completely before adding more.
• Once combined, put the mixture into the pan and return to a very gentle heat.
• Continue to cook, whisking constantly, until the custard has reached your desired thickness – this usually takes about 10 minutes but will depend on how runny you want your custard to be. You must whisk the custard constantly to avoid it going lumpy.
• Remove from the heat and continue to whisk for another minute.
• Serve.

If you’re making the custard to use later

• Put the custard into a bowl or jug and cover with cling film. It is important that the top of the custard is in full contact with the cling film to prevent a skin forming while the custard cools.
• Place into the fridge until you’re ready to use it.
• When you want to use the custard, reheat in a pan, stirring regularly to ensure that a skin doesn’t form. You’ll find that the custard will thicken further as it reheats. It it starts to become too thick, simply add a little more milk to get it to your desired consistency.