In a medium-large saucepan or Dutch oven, melt the butter. When it foams, add the potatoes and onions and stir until well coated. Sprinkle with salt and a couple grinds of freshly ground black pepper. Reduce heat to low and cover the pot. Cook for 10 minutes until veggies are softened.
Add the fresh spinach and cover the pot for 5 minutes to allow the spinach to wilt.
Add the diced bread and stir gently but thoroughly to coat the bread. Cook 10 for minutes, stirring frequently, until croutons are a light golden and crisp. Remove from heat and allow to cool before storing in an airtight container.
See Café tips for further instructions and tips.
Adapted from Simply Delicious by Darina Allen