Cook the base grain. Prepare rice, quinoa, or farro according to package directions.
Fluff and set aside. For extra flavor, add a pinch of salt and a drizzle of olive oil after cooking.
Prep the fresh toppings. Halve the cherry tomatoes, slice the cucumber and red onion, and pit/slice the olives if needed. Crumble the feta.
Keep everything in separate bowls so you can assemble quickly.
Make the meatball mix. In a large bowl, combine 1.5 pounds ground turkey, 1/2 cup breadcrumbs, 1 beaten egg, 1/2 grated onion (with juices), 2 minced garlic cloves, 2 tablespoons chopped dill, 2 tablespoons chopped parsley, 1 teaspoon dried oregano, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, and the zest of 1 lemon. Mix gently with a fork or your hands until just combined.
Shape the meatballs. Lightly oil your hands and form the mixture into 1.5-inch balls. You should get about 18–22 meatballs.
Place on a parchment-lined baking sheet or plate.
Cook the meatballs. Heat 2 tablespoons olive oil in a large skillet over medium heat. Add meatballs in a single layer without crowding. Brown on all sides, turning every 2–3 minutes, until cooked through, 10–12 minutes total.
Work in batches if needed. Alternatively, bake at 425°F (220°C) on a lined sheet for 12–15 minutes, then broil 1–2 minutes to brown.
Make a quick lemon drizzle. In a small bowl, whisk 2 tablespoons olive oil with the juice of 1/2 lemon, a pinch of oregano, salt, and pepper. This brightens the bowls and keeps them moist.
Assemble the bowls. Add a scoop of grain to each bowl.
Top with meatballs, cucumber, tomatoes, red onion, olives, and a spoonful of tzatziki. Drizzle with the lemon-olive oil mixture. Finish with feta and extra dill or parsley.
Taste and adjust. Add a pinch of salt, an extra squeeze of lemon, or a crack of pepper if needed.
If you like heat, sprinkle red pepper flakes.