Pull eggs out of refrigerator to bring to room temperature. Melt chocolate, butter, and oil in a double boiler. Set aside to cool completely. (Using warm chocolate will make your brownies dry and heavy.)
Preheat oven to 350 degrees. Line 9x9 pan with parchment paper.
In a large bowl, beat eggs and sugar for at least 3 minutes. Add vanilla, and salt and beat well.
Add cooled chocolate mixture into eggs and sugar and stir by hand. (Do not use an electric mixer for this step.)
Before it is completely mixed in and uniform in color, add flour and stir a few times by hand.
Before flour is completely mixed in, add in milk chocolate chips and slowly stir.
Pour into 9x9 pan and bake at 350 degrees for 25-28 minutes. Cool.