In a large measuring cup or medium bowl, whisk together the vegetable oil, granulated sugar, vanilla extract, and milk until well combined.

Add the egg and whisk until the mixture is smooth and slightly pale.

Gently whisk in the self-rising flour until just combined and no dry flour streaks remain. Do not overmix.

Divide the batter evenly between 2 large mugs, filling each mug no more than halfway to allow space for the cake to rise during cooking.

Microwave each mug separately for 1 to 2 minutes, or until the top of the cake is firm but still springy to the touch. If the top is very wet, microwave for an additional 10-20 seconds.

Let the mug cakes cool for about 5 minutes; then top each with ¼ cup sliced strawberries, a sprinkle of lemon zest, and a generous dollop of whipped cream. Serve immediately and enjoy!