So so simple peanut brittle

I made this at 5:30 pm today. Now, nearly 8 hours later, the peanut mixture is still not hardened. It tastes sweet and nice, no doubt, but it did not harden. However, I had also made another batch but in a slightly different way that turned out amazingly good. I used 1 1/2 cups peanuts, 1/2 cup sugar and 2 tsps. margarine(You can also use butter instead of margarine). I combined all these in a heavy skillet and cooked over medium heat, stirring constantly, until the sugar was melted and golden in colour, and, the nuts were toasted. It took about 7-8 minutes. Then, I spread the peanuts on an aluminium foil, allowed it to cool and after sometime, I separated them. It was over in no time. Do try it this way, you'll love them.