I like to measure everything out first. It makes mixing much faster and prevents mistakes. Make sure your cocoa and flour are sifted for a smooth batter.
In a small bowl, I combined flour, sugar, cocoa powder, baking powder, and salt. Whisking them together evenly helps avoid clumps and ensures a uniform chocolate flavor.
Next, I poured in milk, vegetable oil, and vanilla extract. I stirred gently until the mixture was smooth and glossy. The batter should have a thick but pourable consistency.
I folded in the chocolate chips carefully, reserving a few for the top if you want an extra melty finish. These will create that signature gooey lava center.
I divided the batter into two microwave-safe mugs. Cooking for about 1 minute 30 seconds on high worked perfectly, but I checked after 1 minute 15 seconds to avoid overcooking. The cake should rise slightly and remain soft in the middle.
Once done, I let the cakes cool for 30 seconds to a minute. The molten center is best enjoyed warm, so serve straight from the mug for the ultimate indulgence.