Preheat the oven to 350°F (175°C).

Melt the butter in a saucepan over low heat.

Add the flour and stir constantly until fully incorporated.

Slowly stir in the half-and-half cream.

Cook, stirring with a wire whisk, for about 2 minutes, until thickened and smooth.

Add the Parmesan and Blue Cheese and stir until melted.

Remove from heat and beat in the egg yolks one at a time.

Transfer the cheese mixture to a large bowl and season with salt and pepper.

Ensure the mixture is slightly overseasoned to enhance the flavor.

Beat the egg whites and cream of tartar to soft peaks.

Carefully fold the egg whites into the cheese mixture until just combined.

Divide the mixture evenly amongst 8 buttered 4 x 2 1/2 inch ramekins, filling them to about 1/4 inch from the top.

Place the filled ramekins in a shallow roasting pan.

Pour enough hot water into the pan to come 3/4 inch up the sides of the ramekins.

Bake for 40 to 45 minutes, or until the tops are set and brown.

Remove the ramekins from the water bath and let cool to room temperature.

At this point, the puddings can be kept at room temperature for several hours, or covered in plastic wrap and refrigerated for up to 2 days.

To serve, preheat the oven to 400°F (200°C).

Run a knife around the edges of the puddings to loosen them.

Gently unmold each one onto the palm of your hand, then place right side up on a greased ovenproof dish.

Drizzle 1 tablespoon of heavy cream over the top of each souffle.

Bake for 15 to 20 minutes, or until the cream is slightly browned and bubbly.

Garnish with parmesan shavings and chopped fresh chives to serve.