Lay the lemon slices in a single layer across the bottom of the slow cooker insert. This creates a natural rack that keeps the salmon off the bottom and infuses it with lemon flavor as it cooks.

Pour the vegetable broth into the insert around the lemon slices. Add the sliced garlic and fresh dill sprigs to the broth.

Pat the salmon fillets dry with a paper towel, then drizzle lightly with olive oil and season both sides with salt and pepper. Place the fillets on top of the lemon slices in a single layer.

Cover and cook on LOW for 1 hour and 30 minutes. Start checking at 90 minutes. The salmon is done when it flakes easily at the thickest part with a gentle press from a fork, or when an instant-read thermometer reads 125 to 130 degrees F for medium doneness. Do not cook past 145 degrees F or the texture will turn chalky.

Carefully lift each fillet out using a wide spatula and place on plates or a serving platter. Ladle some of the warm lemon dill broth over each piece and garnish with fresh dill. Serve immediately over steamed rice or with roasted vegetables.