This slow cooker 3-ingredient dark beer beef roast is straight from my uncle’s playbook for an effortless but seriously impressive festive dinner. He swore by this “drop it in and walk away” method for holidays when the house was full and the oven was already spoken for. Just a good beef roast, a can of dark beer, and a packet of onion soup mix melt together into the richest, glossy gravy and fall-apart tender meat.