Heat oven to 400 degrees.

Spread 1 tablespoon butter on bottom and sides of a 6-cup souffle dish (I used a rubber spatula).

Sprinkle in 1/4 cup parmesan cheese, turning to coat completely.

Melt 3 tablespoons butter in a small pot over medium heat.

Stir in flour. Cook 1 minute.

Whisk in milk and bring to a simmer. Cook 1 minute, until thickened.

Stir in kale, 1/2 teaspoon salt, nutmeg and pepper.

Whisk egg yolks in a large bowl.

Slowly stir a third of warm kale mixture into yolks (Mixing too quickly could cause eggs to scramble).

Stir in remaining mixture and 1/2 cup parmesan cheese.

In a separate bowl, beat egg whites, cream of tartar and 1/8 teaspoon salt on low speed for 1 minute.

Increase speed to high and beat 1 to 2 minutes, until stiff peaks form.

Gently fold egg whites into yolk mixture. Don't overmix or the souffle won't rise properly.

Transfer to prepared dish. Place in oven and reduce heat to 375 degrees.

Bake 35 to 40 minutes, until souffle has risen and is browned.

Quickly insert an instant-read thermometer into center of souffle; temperature should register at least 140 degrees.

Serve immediately.