Preheat a grill to 200℃ and line a baking tray with aluminium foil.
Spread out the asparagus spears flat on the tray and add the cheery tomatoes and corn kernels.
Drizzle with olive oil and season with a little salt.
Place under the grill (I use the second shelf so it's not too close to the grill). Cook for 5 to 10 minutes, shaking the tray halfway through so that vegetables don't burn on the top.
While the vegetables are cooking, toast the pumpkin and sunflower seeds in a fry pan until they start to brown a little (they may pop in the pan, too). Remove form heat and set aside.
When the vegetables are cooked, arrange them on a flat plate. Zest the lemon over the top of the vegetables, then garnish with parsley leaves and toasted seeds. Serve immediately or at room temperature.