Ooey, gooey, chewy, oh so chocolaty brownies!
In a large microwaveable bowl melt the butter.
To the butter add the canola oil, granulated sugar, brown sugar, salt, eggs, egg yolks and vanilla extract. Mix until fully combined.
Next add the cocoa powder, cornstarch, and flour. Just mix until combined.
Pour the batter into an 8x8 inch pan or for thinner brownies, a 9x13 inch pan. Bake at 350°F for 25-30 minutes.