He eats vegetables?
Quit while you're ahead.
Keep on offering pasta or whatever else you're cooking, but I wouldn't be heavy-handed here at all. Serve a little of the family nightly meal alongside the food you know he'll eat. If he has some, don't make a big deal out of it. If he doesn't, likewise.
The big thing is to avoid making a fuss of your child's eating habits and to keep personal confrontation out of the picture, even though you really, really want to lay down the law.
I had a few picky eaters myself. They all grew out of it by their late teens. There is no overnight resolution to the problem, no magic wand that can be waved, much as you would like some immediate solution. Your frustration is completely understandable - it can be incredibly maddening, and very tiring for the cook.
While a huge amount of the solution to the problem is out of your hands and firmly in the child's, you do have it in your power to not make the problem worse, to not shame your child.
I'd advise you to take a step back and try to reframe the problem in your own head. Call it 'DC's temporary difficulty' or focus on addressing your own fears or frustrations. As a parent, it's important to pay attention to your own 'mental game'. Otherwise, your approach can become very reactive as opposed to responsive.
Have him help you plan and prepare meals, and try to keep interaction on the topic of food lighthearted.