Preheat oven to 180°C (350°F). Grease with butter or nonstick cooking spray a 20 cm (8 inch) spring cake form. Set aside.
In a medium mixing bowl beat on high the eggs with ⅔ cup white granulated sugar until light and fluffy. This will take about 5 - 6 minutes.
Add the melted butter, vanilla and milk. Beat on low until well combined.
Stir in flour, baking powder and salt and beat on low until just combined.
Pour the batter into the prepared form.
Lay the diced rhubarb onto the top of the batter and sprinkle with the remaining 2 tablespoons of granulated white sugar.
Bake for 30 minutes, or until the toothpick inserted into the center comes out clean.
Allow to cool for about 20 minutes in the form, before taking it out and cooling completely on a wire rack.
Serve with a side of fresh fruits and berries and a bit of whipped cream.
Enjoy!