Reduce by half and strain into a clean pan.

Drain the vegetables, reserving the stock in a clean pan.

Whisk in the hot milk and pour the mixture into a clean pan.

Pass the mixture through a food mill and place in a clean pan.

Strain into clean pan; return to simmer over medium heat.

Melt the remaining 55g/2oz of butter in a clean pan.

Return the mixture to a clean pan and warm over a low heat.

Strain the now flavoured oil into a clean pan and heat.

Reynolds Release, he noted, can be thrown away, leaving a clean pan behind.

Meanwhile, pour enough water into a large clean pan with a lid to come about cm/ in up the sides.