Preheat oven to 350º.

Bring a large stockpot of water to the boil over high heat.

Meanwhile, remove the thick stems from the greens. Rinse greens and drop them, along with a tablespoon of salt, into the boiling water. Cook for 3 minutes, then remove with tongs to a colander in the sink.

While the greens drain and cool, pour buttermilk into a small saucepan and gently heat.

Melt butter in a medium saucepan over medium heat. Add shallots and garlic and sauté until translucent, about 10-12 minutes. Stir in flour and cook, stirring, for about 10 minutes. Lower heat if garlic starts to brown.

Slowly add warmed buttermilk, about a quarter cup at a time, stirring to incorporate each addition. You may want to increase the heat a bit to help the sauce thicken. Stir in cheese, cayenne and salt. Remove from heat.

Now squeeze all the water out of the drained greens, either with your hands or by wringing them in a dishtowel. Roughly chop them and stir them into the sauce. Pile greens into a small casserole.

Heat olive oil in a small skillet and add puffed rice, stirring to coat. Sauté until they start to color. Season with salt and pepper.

Sprinkle puffed rice over the top of the greens and slide the casserole into the oven. Bake until everything is golden and bubbly, about 20 minutes. Serve hot or at room temperature.

This dish may be reheated, covered with foil, in a 375º oven for 15 minutes. Uncover for the last 5 minutes.