
It's not a good idea to put your tablet on your work surface when you're following a recipe: there are always lots of objects and utensils around, and there's a high risk of it picking up bits of food or preparation in progress, so an "accident" is bound to happen.
And if it's flat, it's not the best angle for reading either.

To make your own inexpensive one, cut or salvage a sheet of thin plywood larger than your shelf, and screw a small piece of cleat of the same width to the bottom. This will support the shelf.

On the back, screw another piece of cleat so that it's tilted, and cobble together a hanging system, here a small piece of pvc tubing, sawn and screwed to the shelf.

Mine is designed to hang on the kitchen towel dryer, but you can easily make it a tabletop model rather than a hanging model.