mixing a tone matching teak wood filler  

If I had to fill that void I'd use solid material. If the area were to be painted or veneered and just needs leveling I might use a two-part filler like Bondo. Forget the sawdust filler idea for an area that large.
What's your plan for the next step?

Thanks for throwing in tkt.,
well, I really was just hoping to fill in and then cover the area of concern with a new handle.
This is not a particularly important desk...its just a little desk I am trying to give new life and the wood handles were designed poorly in that each of them eventually broke apart at the pull/ lip from the weight in the drawers and the pulling action...I am hypothesizing...they we're broken when I got them....the previous owners glued and nailed the lip back on but it still broke further.
I was just hoping to fill in the gap that was part of the hollowing of the old handle...maybe use oil or tint to just make it look similar so that the little bit you see from the side is homogeneous .
In the picture attached the handle is moved over a little to show where it is covering the gap...it can fully cover the mark from the top but you would be able to see a little of the scar from the side .
I was hoping by filling in the centre, sanding it I would have a new surface to attach the new pull onto and would be a relatively decent fix without moving too far past my skills.
**sorry side shot photo is poor but I just wanted to show that the new handle floats a little from the surface thus giving a view of the scar from the side at a certain angle 🙂

Well, the Bondo wood filler is tan-colored, quick, and pretty strong stuff as far as providing structure, holding fasteners, etc. I guess I'd probably recommend that and then painting out the small visible areas with artist's oils or acrylics.

thanks tktoo, I will try the Bondo. thanks for your time and advice

The Bondo stuff starts to set up pretty quickly so prepare to work fast. Mask off the surrounding veneer that's in good condition with blue painter's tape and try to level the filler while it's still pliable with a putty knife or spatula. You can refrigerate the filler and catalyst to delay the reaction somewhat, but it's important to thoroughly mix the two components and get it in place as quickly as possible. Mixing proportions are fairly forgiving, but, generally speaking, the higher the percentage of catalyst and the higher the working temperature, the sooner it kicks. Remove the masking tape before the filler hardens and level the fill by sanding carefully with a block soon thereafter, again before the filler fully hardens. If you have to make two or more applications, wait a day between and wipe the surface with a rag dampened with fingernail polish remover or acetone to help with adhesion between coats. You'll need to re-oil the entire drawer front, perhaps twice, after everything fully cures and before inpainting the fill. Post with update of your results and/or for tips on inpainting if there's need. Bon chance!
Oh, and, if you think of it, spread some leftover filler onto a piece of scrap wood or stiff cardboard while you're working and you'll have the ideal surface onto which you can experiment with inpainting techniques!