Take a saucepan and add some oil in it. Put it to medium heat and try to use a small pan to make the fudge thicker. Take another saucepan and add milk to it. Add sugar to the milk and stir it gently. Put the saucepan with milk on medium heat and don’t forget to stir it constantly. Keep stirring until the sugar is dissolved and the butter is melted. Only then, increase the heat to medium high. Let it heat for a while and when the boil comes, cover it with the lid. Let it boil for another couple of minutes. After that, remove the cover.
Now, do not stir and wait for some time. Take a candy thermometer and attach it to the side of the pan. Let the mixture boil over medium low heat. Keep heating it until it reaches 240 degrees. It will take around half an hour and in the meantime, do not sit quietly and prepare an ice water bath.
Now, you need to remove the pan from the heat. Once it is removed, dip the base of the pan in the ice water you prepared earlier. Let it dipped for 5 to 10 seconds then take it out. Let the fudge cool down at the room temperature afterwards and do not stir in the meantime. You can see the thermometer attached to the pan that you installed earlier. Read the thermometer carefully and see when it says 122 degrees.
When the temperature of the pan is 122 degrees, you will see that the mixture is lukewarm. It can take around 40 minutes to reach that stage. If you intend to use food colour add one drop at that very moment. Now take a wooden spoon and stir the fudge gently. Wait until the fudge is opaque from glossy and is thick as cream. Keep stirring for around 5 minutes.
Now pour the fudge into another pan and use a plastic wrap to pour the fudge smoothly. This will create an even surface of the fudge. Let it cool completely. It will take from 2 to 3 hours depending on your room temperature. Now using 1 1/2-inch heart cookie cutters, cut the fudge in heart shapes. You should oil the cutters before using to make perfect heart shapes. The fudge is ready to serve.