Preheat oven to 220°C/200°C fan-forced. Line a large baking dish with baking paper.
In a large bowl, toss together garlic, lemon juice, potatoes and half of the oil. Season well. Transfer to prepared baking dish. Arrange cabbage wedges and lemon halves among potatoes. Top with pork steaks. Drizzle with remaining oil. Season pork steaks.
Bake for 35 minutes, or until potatoes are tender and pork steaks are beginning to brown. Remove from oven and add peas and sage leaves. Return to oven and cook for a further 5 minutes, or until sage is crispy and peas are warmed through. Serve.