Fill a large pot three-quarters of the way with water and bring to a boil.

Meanwhile, prepare a large bowl of ice water.

Add collard greens to pot and submerge well in water.

Return water to a boil and cook greens for 10-15 minutes, or until tender.

Using tongs, transfer greens to the ice water.

Drain the greens well, then squeeze excess water out using a kitchen towel.

In a large skillet or Dutch oven, melt the butter.

Add the shallots and garlic and cook over medium heat until softened, about 5 minutes.

Stir in the oatmilk and simmer, stirring occasionally, until reduced by half, about 20 minutes.

Add the greens and toss until warmed through, about 5 minutes.

Add parmesan cheese and salt and stir well. Serve warm.