This is my recipe which I tweaked from a couple of recipes I found online. It was years ago though so I can't credit the originals any more.
8x12" tray, if you use a different size it changes the cooking time.
In my oven, using this tray size, it takes 23 mins at 170°C (fan), but again this can vary with different ovens, so keep checking after 20 mins as you want the cocktail stick still slightly sticky, but no uncooked batter.
FUDGY BROWNIES
230g melted salted butter
3 tbsp vegetable oil
260g natural golden sugar
200g any dark brown soft sugar, eg, muscovado
228g eggs (weigh with shell on) at room temp
10ml salted caramel essence (or any you want)
¾tsp salt
135g plain flour
100g cocoa powder
190g chocolate chips, or a mix of choc chips and nuts
METHOD
Put oil, butter and both sugars into a bowl and whisk well.
Add eggs and essence and beat until lighter in colour.
Sift in flour, cocoa and add salt and fold in gently until just combined.
Fold in the choc chips, leaving a small handful aside to sprinkle over the top later.
Pour batter into tray and sprinkle over the remaining choc chips.
Bake just above middle shelf at 170°C for 23 mins or until just set.
PLEASE DO NOT OVERBAKE!!!
Once you figure out the timings for your particular oven this makes the best brownies I've ever tasted.