In a food processor, process the macadamias until roughly the same size as breadcrumbs. Place in a frying pan over medium heat with breadcrumbs, oil and ¼ tsp salt. Cook, stirring, for 5-6 mins or until macadamia mixture is golden brown. Strain the macadamia mixture through a fine sieve into a heatproof bowl, reserving the oil. Spread macadamia mixture over baking paper to cool.
Cook the pasta in a large saucepan of boiling water, stirring often, for 8 mins or until al dente. Drain, reserving ½ cup (125ml) cooking liquid.
Meanwhile, reserve 1 tbs of the reserved oil. Heat the remaining oil in a large frying pan over medium heat. Add the garlic and cook for 30 secs or until just fragrant. Carefully stir in the kale. Season. Cook, stirring frequently, for 2 mins or until the kale wilts. Remove from heat.
Add pasta to the kale mixture in the pan along with lemon rind, 2 tbs lemon juice and the reserved oil. Toss to coat. Stir in the parmesan and season with more lemon juice. Add cooking liquid to loosen the sauce, if necessary.
Divide the pasta mixture among serving bowls. Top with macadamia mixture and season to serve.