Slice the mushrooms, chop the spinach leaves and garlic. Heat the vegetable oil in a pan and sauté the garlic. Add the mushrooms, salt and pepper and fry until the mushroom water has boiled away. Add the spinach and cook for 2 minutes. Season everything again with salt.
For the yeast melt, heat 2 tablespoons of butter in a small saucepan. Stir in the flour with a whisk and gradually add the soy milk. Stir in the remaining ingredients, bring the sauce to the boil while stirring and remove from the stove.
Preheat the oven to 200 ° C. Roll out the puff pastry and cut out 12 circles about 1 cm larger than the dia of the muffin cups. Grease the muffin tray and press the puff pastry into the molds. First pour in the mushroom mass, then the yeast melt. Bake in the oven for 25-30 minutes until the puff pastry and pizza melt are golden brown.