Cauliflower, Bacon and Cheese Macaroni

Ingredients

• 250g dried macaroni
• ½ cauliflower, trimmed, cut into florets (300g)
• 250g bacon rashers, rind removed, chopped
• 80g butter
• 1 brown onion, finely chopped
• ⅓ cup plain flour
• 3½ cups light milk
• 1 cup grated gruyère
• 100g white castello cheese, crumbled
• ½ cup finely grated parmesan
• 2 tbsp thyme leaves – optional, plus extra sprigs, to serve
• ½ cup sourdough breadcrumbs