How to Make the Ultimate Umami-Bomb Vegetarian Demi-Glace
1 small navel orange
1 tablespoon unsalted butter
1 garlic clove, minced
1 pound fresh spinach, stemmed
Salt and freshly ground pepper
Using a knife, peel the orange, removing all the white pith. Cut between the membranes to release the segments; halve them crosswise.
Melt the butter in a medium nonreactive saucepan. Add the garlic and cook over moderately high heat, stirring, until fragrant, about 2 minutes. Add the spinach and toss to coat. Cover and cook until the spinach is wilted, about 2 minutes. Drain off any liquid and season with salt and pepper. Stir in the orange segments and serve.