Spray the bottom of a crockpot with cooking spray. Dice bell pepper and onion.: The moment you spray, you should hear a faint hiss and see the sheen form, which prevents sticking and makes cleanup painless. Spraying evenly means the loaf will release cleanly, so coat the base and a bit up the sides. A common slip is not spraying enough, which causes the meat to adhere during cooking; that leads to tearing when you remove it. If your spray is low, use parchment or a slow cooker liner as a backup.
Add ground turkey, oregano, bell pepper, onion, egg, bread crumbs, tomato juice, salt, and pepper to a large bowl; mix until well combined. (Using your hands is messy, but usually works the best!) Shape into a loaf and add to the crockpot.: As you chop, the bell pepper will smell sweet and the onion will give a sharp, fresh aroma that mellows as it cooks. Aim for uniform pieces so they cook at the same pace and distribute through the loaf. Rushing this step leads to uneven texture, with some bites having large crunchy pockets while others are too soft. Keep a damp towel under your cutting board to steady it, and use a sharp knife for clean cuts.
Cover and cook on low for 5-6 hours. When meatloaf has 30 minutes left, add ketchup to the top, then replace the lid and continue to cook.: Once combined you should notice a cohesive, slightly tacky mixture that holds its shape when pressed. Mixing by hand helps you feel when the ingredients are evenly distributed, and the aromas of oregano and onion become more integrated. Overmixing will pack the meat too tightly and make the meatloaf dense, so stop once the elements are evenly incorporated. If the mix feels too wet, a touch more bread crumbs helps; if it feels dry, a few drops of tomato juice can soften it.
Meanwhile, prepare the salad: mince parsley and onion, dice avocado and cucumber, halve cherry tomatoes, and chop apples; add all to a large, sealable container, along with the olive oil, rice vinegar, feta, and pepper to taste. Toss to coat evenly, then seal and refrigerate until ready to serve.: When forming the loaf, it should feel firm enough to hold a shape yet soft to the touch; you will hear a slight squish and feel resistance as you shape it. Placing it in the crockpot, center it so heat circulates evenly. Pressing too hard creates a compact loaf that cooks unevenly, so shape gently. The exterior will not brown like an oven loaf, but the slow steam will create a tender crust.
Allow meatloaf to cool slightly before cutting; serve with salad on the side. (Serving size: 4 ounce slice of meatloaf, 3/4 cup salad): As the cooker runs, a warm, savory aroma will waft through your kitchen and the internal temperature will rise slowly, yielding a uniformly tender texture. The slow, gentle heat allows connective tissues to break down and keeps the loaf moist. A frequent mistake is lifting the lid often, which releases heat and lengthens the cooking time; resist peeking unless necessary. If your crockpot runs hot, check at 4 hours to avoid overcooking.
When meatloaf has 30 minutes left, add ketchup to the top, then replace the lid and continue to cook.: Adding the ketchup late lets it set without becoming diluted, giving a glossy, slightly sweet finish. You will hear a soft simmer and notice the top take on a richer color as the ketchup warms and integrates. If applied too early, the ketchup can break down and lose its tangy lift, so save it for the final stage. Use a spoon to spread it gently for even coverage.
Meanwhile, prepare the salad: mince parsley and onion, dice avocado and cucumber, halve cherry tomatoes, and chop apples; add all to a large, sealable container, along with the olive oil, rice vinegar, feta, and pepper to taste. : As you assemble, the salad will release fresh, bright scents, and the oil and vinegar will emulsify slightly when tossed. The crisp apples and cucumber contrast the creamy avocado and feta , creating layered textures. A common oversight is tossing the salad too early, which causes the avocado to brown; keep it chilled and sealed until serving to preserve freshness. Taste and adjust seasoning before sealing.
Toss to coat evenly, then seal and refrigerate until ready to serve.: After tossing, you should see a light sheen of dressing over the ingredients with juices settling at the bottom. Sealing the container preserves the bright flavors and keeps the salad crisp. Leaving it at room temperature allows the dressing to soften the produce too much, so chill promptly. If the salad seems watery after sitting, drain a bit of liquid and give it a quick toss before serving.
Allow meatloaf to cool slightly before cutting; serve with salad on the side.: When you lift the loaf from the crockpot, the aroma deepens and steam will rise, signaling doneness. Letting it rest for several minutes firms the loaf, making cleaner slices and concentrating flavors. Cutting immediately can cause it to crumble and release juices, so patience pays off. Serve each slice warm alongside a generous portion of salad for contrast and balance.