How would you brace these cabinets to the countertop

I got new countertops put in. There used to be a brace (a piece of wood basically) there that attached the bottom of the cabinet to the old countertops to help support the cabinets weight and keep them from falling. As you can see, right now, I have a piece of two by four wedged in there. I was thinking I'd just put another piece of wood there that was decorative but I don't know how I'd attach it to the countertops. Just wondering what you guys' thoughts were. I hope what I've said makes sense lol