How to do big white outlines on unity UI?

I want to make an outline on some buttons, and these buttons have different shapes. I was doing a test with the Outline component (Add Component > UI > Effects > Outline), and turns out its actually copying the button image four times behind my button and multiplying a color on it. So I can’t change this color to white because that would leave these four images as is. Also if I set the effect distance too high (like more than 4), It’ll start to become weird.

Here’s an image to illustrate

Is there any other solution that I can make an outline the way I want? Something more like the photoshop stroke effect. Something that actually work with the pixels.

Hackish way - create a clone of the sprite with larger scale (for ex. 1.1) and custom material with GUI / Text Shader shader.

Custom material:
[104553-снимок-экрана-2017-10-27-в-223812.png|104553]