When you see a good recipe from a trusted source, all you have to do to be successful is
- find the right ingredients
- respect the quantitative guidelines (weight, time, temperature...)
- follow the process and the correct manipulation of the ingredients (slicing, kneading, assembling...)
But: where is the creativity?
Leftovers, on the opposite, force you to be creative. You already have the main ingredients, and there is no way to find a recipe inserting in google words like "rice+peas+lentils"
Cooking leftovers is like playing music without the piano score. With the recipe you follow the score, without, you have to improvise, like playing Jazz. You blend together ingredients (like notes) expecting one harmonic final result.
I had lentils (leftover from a lentils cream with shrimps), boiled rice (leftover from a Curry almond Chicken), and peas (a former side dish to a grilled salmon).

What guided my "creativity" was the size of the three ingredients: all of them were made of little components, so was natural for me to think about mixing them together in order to create meatless meatballs, or Veggyballs

(it should be time to use some neologism, instead of keeping the "meat"name also where there is no meat)

Now I needed some creamy and flavoring additions:
grated Parmesan and Yogurt

and some "bonding" substance: two eggs

What better than sharp provolone to be the cheesy heart of my Veggyballs?

and for exterior we need a crunchy crust, made by Panko (or breadcrumbs)with some flavor like garlic and lemon-pepper.

After mixing well the wet ingredients and the dry ones, we are ready to assemble our patties, putting the provolone in the center and folding around the rice mix.

I roll each veggyball in the savory Panko and put it on parchment paper over a baking sheet to be put in a oven at 450F (sorry, I don't fry at home for health reasons: my wife would kill me

)
I know, the shapes of the balls are quite irregular, but I thought that the rustic ingredients should be well depicted by the rustic appearance.

after 20 minutes at high temperature , the patties come out well browned and promising toasted.

Sorry for the poor quality of the photos (out of focus); we served the veggyballs with salad and cherry tomatoes. I have to be quite proud of the end result: savory and soft interior enveloped in a flavorful crunchy exterior.

the heart was the additional layer of flavor

and the melted provolone was the real treat.

Yes, a good use of leftovers, so good that it could be an original recipe to create from scratch.
(no, dont' even think about that: boiling rice, cooking lentils and peas just for that... no way. Better to wait for the next amount of leftovers and keep creating.)