Kids at that age tend to be separatists, and so fancy casseroles and elaborate dishes are out of the question. They like the cheese bits in one spot, the cheerios in another, and the carrot pieces in another. In many cases, it is taboo for any of them to touch each other. They like little pieces of cut up food that they can pick up and feed themselves, or something so clumpy that it will stick to their spoon on its perilous and roundabout journey to their mouth. Don't worry too much if they don't all make it.
Snacks are a great way to fill in what was missed at the previous meal.
In the case of your twins, get a daily diary of what they eat at day care so that you can tailor their meals at home to round out their daily diet. You can prepare a meal for them quickly and easily but recognizing those foods in each group that lend themselves to little or no preparation time. On the weekends you can make a meatloaf, cut it into fingers and keep refrigerated to serve during the week, or freeze for later use. On weekends you can also make mini meatballs that freeze well for later use. From the fruit and vegetable group, serve soft, ripe, peeled fruit such as bananas, peaches, melon, mango, papaya, and pear.