Is it possible to add a method to an engine class via a plugin?

I want to implement additional methods for the engine’s FCanvas class. I know I can recompile the engine and add that new functionality inside the Canvas.cpp, but is it possible to add it from a plugin?

If that’s possible, how so?

If that’s not possible, what would be the cleanest way to add functionality to an existing class (from a plugin)?

Thanks in advance!