- Preheat oven to 425 degrees Fahrenheit.
- Spread 1 tbsp butter over sheet pan. Optionally, cover the sheet pan in foil first for easy clean up.
- Spread tomatoes, onion, squash, half of the lemon, and salmon fillets skin-side down in a single layer on the sheet pan.
- Whisk dill spice blend into remaining butter and drizzle evenly across the vegetables and salmon. Bake pan on the middle rack for 15 minutes until salmon is light pink and flaky.
- Garnish with remaining lemon slices and fresh dill. Serve warm.