Preheat a fan-forced oven to 160C (320F) or 180C (356F) for a conventional oven. Spray two 8” cake tins with oil spray and line the bottom with baking paper.
In the bowl of a stand mixer fitted with the paddle attachment, add the flour, baking powder, caster sugar and salt. Turn mixer on low speed and allow it to mix for a couple minutes to help everything combine well (alternatively you may do this by sifting the ingredients together). Add the softened butter and mix until it resembles a fine sand like texture.
Add the milk, oil, Greek yogurt, eggs and vanilla extract into the bowl with the dry ingredients and mix on medium speed until no dry ingredients are visible. Scrape down the bowl, add choc chips and fold in. The Greek yogurt is optional and helps keep the cake moist.
Fill cake tins with batter.
Bake for 30 min or until a toothpick inserted comes out clean. Allow the tins to cool for 2 min and then carefully flip the cake tins over on to a cooling rack to cool completely before using.
Using a large serrated knife, carefully trim the top off each layer of cake to make even and flat layers. Try to aim to get them all the same height. An easy way to do this is to find the lowest height of the cake, place a skewer or toothpick next to that point and mark it. As you go around each side of the cake cutting it, use the marked skewer to make sure each cut is at the same height.