best way to create simple bevel outline?

I have a complexly-shaped plane, and I need to bevel it so that there is a outline around it (for the sake of illustration, imagine a gingerbread cookie with a frosting outline). I thought that extruding it and then scaling down the vertices would work for that, but the scaling clips into the edges and it doesn’t do it uniformly. This seems like an easy thing to do, any suggestions?

You can extrude the entire thing and use a bevel modifier. Then if you need the bevel to stick out from the surface you can extrude the faces back under the top of the bevel. Then you can use loop cuts and turn on proportional editing to shape the bevel if its not quite what you want.

If it is only for visuals and not required to be a physical bevel you can go to the render settings and turn on edge rendering under the “Post Processing” group.