Caramelized Onion and Eggplant Frittata - Sprinkles & Sea Salt

Ingredients

• 2 tbsp unsalted butter
• 3 medium sized onions, sliced thin (about 2.5 cups sliced)
• 1 1/2 tsp salt, divided
• 2 cups eggplant*, cubed
• 2 large cloves garlic, crushed
• 6 large eggs
• 1 cup whole milk
• 1/2 cup white all-purpose flour
• 1 tsp baking powder
• 1/4 tsp oregano
• 1 cup + 2 tbsp shaved parmesan cheese
• 2 cups arugula