Ellipse Shape Groove in Design

Hello, I want to learn to design molds .. I am new on Solidworks, and also in this forum. This is the part I have

And the actual design in metal

How do I make the Ellipse Shape Groove in the design?. If I select Extruded Cut, it will make it a hole, I only want it to be a groove

SolidworksPlastics And Mold Design