If using frozen spinach, cook according to package instructions.
If using fresh, cook in a large pot until reduced to about 3 cups.
Drain and set aside.
Drain the potatoes and return them to the pot.
Add the spinach, mustard, sour cream, butter, salt, and pepper.
Mash until the desired consistency is reached.
Notes / Tips / Wine Advice:
Serving Tip:Serve warm as a side dish to roasted vegetables or grilled plant-based protein.Wine Advice:A crisp Sauvignon Blanc or a light Pinot Noir complements the mustard and spinach flavors well.