Growing Glutes

Hi All,

This year I've lost about 90lbs and with that, I lost my entire butt. Now that I'm in maintenance mode and not focused on losing any more weight, I'm more focused on gaining muscle, particularly in my glutes. I start on the floor and lift heavy and then I power walk on the treadmill at an incline.

My question is... in order to work my glute muscle more, is it better to go slower at a high incline or faster at a high incline?

ETA: Thank you for the responses. I understand how to grow my glutes and exercises to do outside of the treadmill. I was just asking for the tread advice because since I go to OTF 4-5x a week, I wanted to know what the best option was.