Preheat the Oven: Heat the oven to 400°F so it’s ready when the pan goes in.
Slice the Fennel: Trim the fennel bulb and thinly slice it into curved strips. Set aside for the bean mixture.
Make the Citrus Mayo Topping: In a small bowl, whisk together the mayonnaise, crushed red pepper, half the minced garlic, and 2 teaspoons of the orange zest until smooth and well combined.
Coat the Fish: Line a baking sheet with aluminum foil. Place the fish fillets on the sheet and spread the citrus mayo mixture evenly over the top of each fillet.
Season the Beans and Vegetables: In a large bowl, combine the green beans, cannellini beans, and sliced fennel. Add the olive oil, rosemary, the remaining minced garlic, and the remaining 1 teaspoon orange zest. Toss until everything is evenly coated.
Arrange on the Pan: Spoon the bean-and-vegetable mixture onto the baking sheet around the fish, keeping the fish clear so the topping stays on top.
Add Citrus and Almonds: Scatter the orange segments over the bean mixture, then sprinkle the sliced almonds across the beans and oranges.
Bake: Bake until the fish flakes easily with a fork and the almonds look lightly toasted, about 15 minutes.
Serve: Plate the fish and spoon the warm beans, green beans, fennel, oranges, and almonds alongside. Enjoy your low-effort glow-up meal.