Preheat oven to 375 degrees F (190 C) and prepare flax egg in a small dish.
In a large, deep skillet, sauté onion and garlic in 1/2 Tbsp olive oil over medium heat until soft and translucent - about 3 minutes. Set aside.
Add tempeh to food processor and pulse to break down. Then add sautéd garlic and onion remaining ingredients (except olive oil) and mix, scraping down sides as needed. You want it to form into a moldable “dough.”
Taste and adjust seasonings as needed. The tempeh will come across as a little bitter, but once coated, baked and served with marinara it's not nearly as apparent.
NOTE: Depending on how salty your vegan parmesan cheese is, you may need to add a little salt and pepper at this point. However, I didn’t find it necessary.
Scoop out 1 Tbsp amounts of dough and roll into balls. At this time, heat the same skillet you used earlier to medium heat.
Mix remaining bread crumbs and parmesan cheese together in a shallow dish. Add tempeh balls one or two at a time and roll to coat.
Add enough olive oil to form a thin layer on the bottom of your hot skillet, then add your coated tempeh balls in two batches, as to not crowd the pan. Brown for about 5 minutes total, shaking the pan to roll them around to brown all sides.
Add browned meatballs to a baking sheet and add to the oven to bake for about 15 minutes, or longer if desired for a crispier result.
At this time, prep any pasta your want to serve with your meatballs, as well as your favorite marinara sauce (I love this pizza sauce).
Once meatballs are deep golden brown and fairly firm to the touch, remove from oven.
To serve, top cooked pasta with meatballs and pour over marinara sauce. Top with another sprinkle of vegan parmesan cheese and fresh parsley. Leftovers will keep in the fridge for up to a few days, though best when fresh.