Finely crush breadcrumbs, either in a blender (easiest method) or by placing them in a bag and crushing with a rolling pin or heavy object.
Preheat oven to 425 F. Cut cauliflower into florets, carrots into diagonals, onion into strips, and trim ends off snap beans.
Whisk milk, cornmeal, and oil, then toss with the cauliflower in a large ziploc. Put the cauliflower in a colander to drain off excess batter.
Toss with the breadcrumbs.
Arrange cauliflower in one layer on a parchment-lined baking sheet. Bake for 15 minutes. In a bowl add 1 tsp of olive, and coat remaining vegetables. Season with salt and pepper and place in a single layer on the same baking sheet. Separate from cauliflower. Cook for another 15 – 20 minutes.
While vegetables are cooking, prepare 1 cup of rice according to package instructions. Once cooked add the zest of the lemon, stir.
Make the lemon sauce by whisking together all remaining ingredients (use 1 tsp of minced garlic) in a small pot, except cornstarch. Then quickly whisk in cornstarch. Turn heat to medium. Stir frequently – it thickens pretty quickly.
Remove cauliflower from oven and stir into the sauce. Add remaining garlic to baking sheet and mix with other roasted vegetables.
Place rice on 4 dishes, and divide the vegetables and cauliflower on each dish. Sprinkle remaining lemon juice for that extra lemon flavor.
