Blanch half a pound of spinach in salted, boiling water.
Immediately, "shock" the blanched spinach in a bowl of iced water. Drain and squeeze out the excess water.
Puree in a blender. Set aside.
In a large skillet over medium heat, sweat the shallots and garlic until translucent.
Add the rest of the spinach leaves. Toss and saute until wilted.
Fold in the spinach puree.
Season with salt and pepper, transfer to a serving bowl and serve immediately.