Preheat the oven to 375 degrees F.

In a large skillet, heat the olive oil over medium/low heat for a minute. Add onion and sauté for two minutes until translucent. Add garlic, stir, and sauté an additional minute.

Add a few handfuls of spinach into the pan at a time. Cover with lid to steam the spinach. Stir and then add in remaining spinach. Cover with lid for a few minutes until all the spinach is still bright green, but wilted. Stir to evenly incorporate the garlic and onion.

Move the wilted spinach to one side of the pan. Pour in the almond milk. Add the yogurt and flour. Whisk to evenly combine and then stir in the spinach. Add the cheese and cook until melted, about three minutes, stirring occasionally.

Add the herbs, stir, and then remove the pan from the heat.

Wipe down the tops of the portabella mushrooms with a damp towel or paper towel to remove any dirt. Remove the stem. Use a spoon to scoop out all the dark ribs from the inside of the cap. That will allow them to hold more filling.

Heat the olive oil in a small pan over low heat. Add the panko bread crumbs and almonds. Stir to evenly coat and cook the mixture until lightly golden and toasted, about 3 minutes. Remove from heat immediately to prevent burning.

Fill each mushroom with three spoonfuls of the spinach mixture. Place mushrooms on small baking sheet. Sprinkle almond and breadcrumb mixture over the mushrooms. Bake mushrooms for 10-15 minutes.

Serve mushrooms right away. Serve on a bed of polenta or over some pasta of your choice. Mushrooms would even be a great side dish to some kind of meat/seafood.