Spinach & cheese puffs

Grease six ovenproof mugs (1½-cup capacity) with melted butter. Coat base and side of each mug with 1 tablespoon parmesan, shaking excess into a small bowl. Place mugs onto an oven tray.

Melt butter in a medium saucepan over a medium heat. Add flour. Cook, stirring, for 2 minutes. Remove from heat. Slowly whisk in milk until smooth. Return to heat. Bring to a boil, stirring, until thickened.

Add remaining parmesan, any excess parmesan in small bowl and Tasty cheese. Whisk until melted. Transfer to a large bowl. Whisk in egg yolks.

Squeeze excess liquid from spinach. Add spinach and pepper to cheese mixture. Season with salt. Stir until combined. 

Beat egg whites in a large bowl of an electric mixer until firm peaks form. Add egg whites in two batches. Using a large metal spoon, gently fold into spinach mixture
until just combined. Spoon enough mixture into mugs to come to 2cm from the top.

Cook in a hot oven (200°C) for about 20 to 25 minutes, or until golden and puffed.

Serve puffs immediately.