The ingredients you'll need
First, make the croutons. Cut the bread slices into neat triangles about 1 inch (2.5 cm) on each side. Melt the 1 tbsp. butter in a frying pan over medium heat. Working in batches, fry the triangles, turning as needed, until golden brown on both sides. Set aside. (If you prefer not to fry the croutons, shake the bread cutouts with a little oil in a shallow baking pan and bake them in a preheated 400 F (200 C) oven until golden brown, 5-10 min)
Rinse the spinach well and transfer to a large saucepan. Cook over medium heat in just the rinsing water clinging to the leaves until tender, a few minutes. Drain well and then press the leaves gently between paper towels or a clean kitchen towel to remove most of the moisture. Chop the leaves roughly and return them to the pan.
Using a fork, mix together the 1/2 teaspoon butter and the anchovies until thoroughly blended. Add the anchovy butter and raisins to the spinach, set the pan over medium heat, and heat, stirring often, until the mixture is piping hot.
Transfer to a serving dish, garnish with the croutons and serve immediately.