Step 1

Melt butter in a Dutch oven over medium heat. Add shallot, and cook, stirring occasionally, until tender, about 3-5 minutes. Stir in garlic until fragrant, about 1 minute.

Step 2

Whisk in flour until lightly browned, about 1 minute.

Step 3

Gradually whisk in heavy cream. Bring to a boil; reduce heat and simmer, stirring occasionally, until reduced and slightly thickened, about 7-8 minutes.

Step 4

Stir in Parmesan, Dijon, lemon zest and nutmeg; season with salt and pepper, to taste.

Step 5

Working in batches, stir in spinach until wilted, about 5-8 minutes.

Step 6

Serve immediately.