High rise!
They really rise high. I think the key is to use self-rising flour AND additional baking powder AND baking soda.

They were still incredibly tender and fluffy, though.

I can’t stop dreaming of these.

Mine didn’t rise as high as yours. Mine are flat!
Hard for me to say why. There are so many factors.

Did you use buttermilk? It reacts to the baking soda and baking powder to help with the rise.

How old is your baking soda and baking powder?

See below on baking powder for more information.

Did you use self-raising or regular flour?

Truly every oven is different, too. That could affect the rise.

Additionally, overworking the dough can affect the rise too.

Another reason your biscuits might not be as fluffy or have a high rise. The SCIENCE behind baking powder.
The TYPE of baking powder makes a huge difference in your fluffy biscuits.

Baking powders can be fast-acting, slow-acting, or double-acting, depending on the acid or acids they contain, according to Shirley Corriher.

“Some acids react with liquid, while others react with heat. Double-acting powders usually contain two acids—one for liquid, the other for heat.”

And there we have it.

What kind of baking powder did you use?

I use double-acting, aluminum-free baking powder (see more below on aluminum-free).

Aluminum-free baking powders react with liquid and not with heat.

This makes them faster acting because as soon as you add the liquid (buttermilk, which has acid in it so it reacts kind of like how when you mix baking soda and vinegar together), you gotta move fast and get these into the oven promptly because most of the bubbles (reaction) are released shortly after mixing.