Preheat the oven to 200°C.
Combine the extra virgin olive oil, garlic, crushed coriander seeds, salt, and pepper in a baking tray.
Blanch the red beetroot leaves in boiling water for 20 seconds, drain, and stir into the oil mixture with lemon zest.
Arrange all beetroot varieties on a baking tray, season with salt, pepper, and both paprikas, then roast for 10 minutes.
Coat the mackerel fillets with oil and season with salt and pepper.
Place smoking chips in the smoker and smoke the mackerel fillets over heat for 6 to 8 minutes.
Quarter the roasted beetroots and drizzle them with honey.
Plate the beetroot leaves, top with mackerel, arrange beetroots around, and garnish with horseradish, pea shoots, and lemon juice.