I stumbled across a place called Baker's Dozen Panaderia in Onarga when I was driving from Champaign to Chicago and looking for someplace to take a break and grab a cup of coffee. It's a tiny take-out place, which sells Mexican pastries (sweet breads and cakes) and a small menu of Mexican dishes such as tacos and tortas, made to order. I'm not an aficionado of Mexican food, so I can't say how authentic it was, but the steak torta I had was quite tasty; and my pastry, a glazed orange sweet bread, was also good.
Exit I-57 at Onarga, go east until you reach an intersection where there's a Casey's General Store, and then turn right. Baker's Dozen is about a block down, on the left (east) side of the street. The phone number is 268-9880 (I don't know the area code). And they do have coffee.