Line an 8 inch pan with foil or parchment paper, set aside.
Grab two medium size bowls.
Place milk chocolate chips into one bowl. Add red gel food colouring and stir until combined. Start with one little dab to start. You can always adjust the colour later. Always best to start with a bit and add more. Once you add too much you can't go back. Set aside.
Pour white chocolate chips into the other bowl. Set bowl aside.
In a small saucepan heat the sweetened condensed milk over medium-low heat. You want it to bubble gently across the top of the milk, and heat through without browning or sticking. This takes a few minutes. Don't walk away from it, stir it occasionally and keep a close eye on it. It can go from warming gently to burning pretty quickly.
Add the salt and vanilla. Stir. Take off heat. Pour half the milk over the milk chocolate chips, and half over the white chocolate chips.
Use a different spoon to stir each one quickly until the chocolate chips melt and the mixture is smooth and thick.
Drop random spoonfuls here and there in the pan. Just drop them all over so they look like patchwork. Keep adding spoonfuls randomly until all the mixture is in the pan.
Take a knife and gently pull it back and forth slowly to create patterns in the fudge. There's no right or wrong way to do it. I drag mine in lines one way, then turn the pan and run them the other way.
Place the pan in the fridge for about 2 to 3 hours, or overnight. You can score it before it completely hardens if you like.
Once fudge is chilled cut into squares.
Serve with a big old red velvet loving smile!