continuing the project of the spoon, I created the variable thickness using two offsets and blending these using a boundary blend. thank you all for your suggestions. I made sure to create the boundary blend from curves that are tangent to both offset surfaces.
unfortunately it is still impossible to create the rounds which are vital for the part, along the top and bottom edges.
What about if you were to make a solid of the existing geometry and then select the outside perimeter surfaces of the spoon (all the way around) and then do an OFFSET, EXPAND by a small amount. Then go back and create a "clean" cut all the way through, from let's say the top view. This cut cannot reference the surfaces you just offset (i.e. offset edges). After you have the "clean" cut, see if you can place the rounds.