Halibut with radishes in citrus sauce

Ingredients:

• 0.7 kg skinless halibut fillet (center pieces), cut into 4-6 pieces
• 1 red onion, cut into 1cm thick wedges.
• 2 bunches radishes, trimmed and halved
• 1 teaspoon fresh thyme
• 3 tablespoons extra-virgin olive oil
• Juice of 2 blood oranges (0.5 cup)
• Juice of 1 red grapefruit (0.5 cup) + 1 whole grapefruit
• Juice of 1 lime
• 1 tbsp. heavy cream
• 110 g chilled unsalted butter, cut into small pieces

Preparation:

1. Preheat oven to 230°C (430°F). On a rimmed baking sheet, combine red onion, radish, thyme, 2 tablespoons olive oil, 3/4 teaspoon salt, and a few grinds of freshly ground black pepper. Bake until tender, 20-25 minutes.
2. Season the halibut with salt and place it on top of the roasted vegetables. Brush with the remaining 1 tablespoon of olive oil. Bake until the halibut is cooked through, about 10 more minutes.
3. Meanwhile, combine the orange juice, grapefruit juice, and lime juice in a small saucepan and bring to a boil. Reduce heat and simmer until reduced to about 1/4 cup, 12-15 minutes. Add the heavy cream and whisk to combine.
4. Reduce heat to low and whisk in the butter one piece at a time, waiting until it's completely melted before adding each new addition. Season with salt to taste. Keep the sauce warm over very low heat until ready to serve.
5. Peel a whole grapefruit, discarding the white pith. Cut between the membranes and remove the segments. Transfer the halibut and vegetables to a platter with a spatula and arrange the grapefruit wedges around them. Drizzle with citrus oil.