Dutch deep-fried bitterballen with cheese and ham

Ingredients

• 100 gram butter
• 120 gram all-purpose flour + extra
• 1 small red onion
• 1/2 liter vegetable stock
• 100 gram dried ham (we've used Coppa ham)
• 125 gram goat's cheese
• 3 tablespoons honey
• pepper and salt to taste
• 4 egg whites
• large handful of bread crumbs