1/2  cup butter 
1/2  cup shortening 
1  cup granulated sugar 
1  cup brown sugar, packed 
3  large eggs 
2  teaspoons vanilla 
2  cups all-purpose flour  
1  teaspoon baking soda 
1/2  teaspoon salt 
2  cups chocolate chips 

1. Pre-heat oven to 180c.
2. In a large bowl, cream together butter and shortening; gradually mix in sugars, creaming thoroughly. Beat in eggs and vanilla.
3. Combine flour, baking soda and salt; blend into creamed mixture. Stir in chocolate chips.
4. Chill for a few minutes or let stand at cool room temperature for 30 minutes.
5. Drop by rounded teaspoon 180°c oven for 8-9 minutes or until golden brown around the edges and still slightly under-baked in the centre. Let stand on baking sheet for 5 minutes; remove to racks to let cool completely.