Frittata with onions and zucchini

20g butter , melted
2 tablespoons olive oil
2 medium (300g) onions, thinly sliced
6 eggs , lightly beaten
3/4 cup (60g) grated parmesan chesse
1 small (90g) zucchini,thinly sliced
1 tablespoon shredded fresh basil
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1. Brush base and sides of deep 19cm square cake pan with butter . Heat oil in pan,add onions , cook , stirring , until onions are soft; cool.
2. Combine onions , eggs , cheese, zucchini and basil in bowl ; mix well . Pour mixture into prepared pan . Bake in moderate oven about 25 minutes or until lightly browned and set .

• Recipe can be made a day ahead.
• Storage: Covered , in refrigerator.
• Freeze : Not suitable.
• Microwave: Suitable.