Blanch the spinach in boiling water for about 2 minutes.
Quickly transfer to a bowl of ice water to stop the cooking process.
Drain well and squeeze out as much liquid as possible.
Melt the butter in a large skillet over medium heat.
Add the chopped onion and saute until it turns translucent.
Stir in the flour and continue stirring until it turns a light golden color.
This should take about 5 minutes.
Slowly whisk in the milk, ensuring no lumps form.
Add the bay leaf and whole clove, then bring the mixture to a boil.
Lower the heat and let it simmer for a few minutes.
Add the drained spinach to the skillet and mix evenly.
Season with salt and a pinch of nutmeg.
Allow the mixture to heat through and reach the desired consistency.