Scottish Tablet

This is from my mom's side of the family.

1L Granulated Sugar
1/2 Cup Butter
1/2 Cup Milk
1 Tin Condensed Milk

Melt butter in a large non-stick pan (a large wok-sized pan works great).
Add sugar and milk.
Bring to a boil slowly, and let boilg for 5 minutes.
Add the condensed milk while stirring.
Boil for 7-10 minutes, continuously stirring.
Take off the heat, and beat with a wooden spoon to let off the heat.
Put into a greased pan and leave to set.
Cut into squares.