Ham and Cheese Croquettes - Ziggys

Ingredients

• 25g butter
• 1/2 small onion, finely diced
• 2/3 cup plain flour (divided)
• 1 cup milk
• 150g Ziggys ham, diced
• 1/4 cup grated mature cheddar cheese
• 1/4 cup grated gruyere cheese
• 1 tsp Dijon mustard
• 2 tbsp double cream
• 2 large eggs
• 140g fine dried breadcrumbs
• sunflower oil for frying