For the meatballs, make sure to mix the two meats together very well. The meatballs can fall apart and have an inconsistent texture if the mixture is not well combined. Also be sure to mince the onion, garlic and kale down to eraser-head size or smaller bits to ensure ease of meatball binding and rolling. Meatballs can be frozen up to 6 months in an airtight bag or container. Thawing is recommended before cooking. For the chimichurri, if you enjoy a more chunky, earthy sauce with less tedious preparation, you can leave some stem on the cilantro and parsley. If doing so, I'd recommend pre-chopping the greens before putting all ingredients into the food processor to avoid large strands of stem. For the mac: If the roux or mac mixture seems a little runny, you can add extra cheese to thicken the consistency. If you need to reheat the mac, add a small amount of vegetable broth and gently stir the mac and broth on medium-low heat until melty and smooth again.