- 4 ounces (Four 1/2-inch slices) sourdough bread, sliced and crust removed
- 1 cup almond milk
- 3 tablespoons olive oil, plus more for greasing
- 1 yellow onion, finely chopped
- 2 pounds mixed mushrooms, finely chopped
- 1 cup ketchup, divided
- 1 tablespoon minced sage
- 1 tablespoon minced thyme
- 1 tablespoon minced oregano
- 2 garlic cloves, minced
- 1 cup walnuts, coarsely ground in a food processor
- ½ cup instant oats
- ½ cup dry bread crumbs
- 2 tablespoons kosher salt
- 2 tablespoons lemon juice
- ½ tablespoon freshly ground black pepper
- 1 teaspoon lemon zest
- 2 eggs, lightly beaten
1. Preheat the oven to 375º. In a small bowl, cover the sourdough bread with the almond milk. Let soak for 15 minutes, then squeeze the bread to release any soaked milk, tear into 1-inch pieces and set aside. Discard the almond milk.
2. In a 6-quart Dutch oven, heat the olive oil over medium-high heat. Add the onions and cook until lightly caramelized, 3 to 4 minutes. Add the mushrooms and cook, stirring often, until any liquid released has evaporated and the mushrooms are lightly caramelized, 10 to 12 minutes.
3. Add half of the ketchup with the sage, thyme, oregano and garlic, and cook, scraping up any brown bits from the bottom of the pot, until the garlic and herbs are fragrant, 2 minutes. Remove from the heat and stir in the reserved bread, walnuts, oats and bread crumbs. Transfer to a large bowl and let cool slightly.
4. Using a wooden spoon, stir in the salt, lemon juice, pepper, lemon zest and eggs until well incorporated. Press the mixture into a greased 9-by-5-inch loaf pan and smooth the top. Brush with the remaining ketchup.
5. Bake the meat loaf for 1 hour, then place on a wire rack to cool for 20 minutes before slicing and serving.