As Alexia said, the best way to balance proteins and carbs in a vegetarian dish is mixing a carb source (rice, pasta, grains) with pulse. All the vegetarian populations have invented plenty of such dishes...just think to indian cooking:
-kitcheree (rice and lentils)
-chana poori (fried bread and stewed chickpeas)
-masala dosa (lentil pancakes stuffed with potatoes and vegs)
and many others.
Being italian, I can remind you dishes like Pasta e fagioli, Risi e Bisi (rice and green peas), Mesciua (grain and bean soup).
Otherwise, some other Pasta or Polenta dish with vegetables, or a rich Risotto, or vegetarian Ravioli.
If cheese is admitted, Melanzane alla Parmigiana, a vegetarian Lasagna, or a "Polenta Concia" (Polenta slices, layered with cheese and tomato sauce and baked...very yummy)
If you can use eggs...but it's better to stop, or I'll go on until tomorrow