Fill a large stockpot with water and season it with enough salt so it tastes like sea water. Bring the water to a boil over high heat. Fill a bowl with ice water and have nearby.

Meanwhile, trim off the leaves of the collards, removing the central rib and stem; discard the ribs and stems. Drop the leaves into the rapidly boiling water and cook in batches, being careful not to drop the temperature of the water. Boil each batch, uncovered, until the collards are tender, about 3 minutes. Transfer each batch to the ice water to stop cooking and cool down.

Once the collards are cool, remove them from the ice water and squeeze them to remove as much water as you can. Chop the collards finely and set aside.

In a large saute pan, melt the butter over medium heat. Turn heat to low and add the shallots, garlic, thyme and bay leaf. Cook the shallots until they are soft and translucent, about 3 minutes. Add the cream, increase the heat to medium and cook until reduced by half, about 5 minutes. Remove the thyme and bay leaf. Stir in the collards (and pepper flakes if you choose to use them) and cook until they are warm and coated well with the cream.

To serve, sprinkle with nutmeg and adjust the seasoning with salt and pepper if needed.