Sourdough discard is the portion of sourdough starter that is removed during feeding to maintain a manageable starter size. Rather than wasting this nutritious starter byproduct, many bakers use it in recipes like muffins, pancakes, and crackers to add flavor and reduce food waste. In this lemon blueberry sourdough discard muffins recipe, key dry ingredients include 240g all-purpose flour, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon salt, and 1 tablespoon cornstarch. These leavening agents ensure the muffins rise properly, giving a light and fluffy texture. The zest from one lemon provides bright, fresh citrus notes that balance the sweetness. The recipe calls for 100g sugar and one stick of melted butter, which combine to impart richness and moistness. Mixing the ingredients until just combined prevents overworking the batter, helping keep the muffins tender. Baking at 350°F (175°C) for 30-35 minutes allows the muffins to develop golden tops while fully cooking inside. Using sourdough discard adds subtle tanginess and complexity to your baking, elevating the flavor beyond traditional muffins. This approach utilizes every part of your starter efficiently, supporting sustainable baking practices. This recipe yields approximately 16-17 muffins — ideal for sharing or freezing for later treats. For best results, fold fresh or frozen blueberries gently into the batter last to avoid bursting. If sourdough discard is not accessible, you can substitute it with yogurt or buttermilk to maintain acidity and texture. Enjoy these muffins for breakfast, brunch, or an afternoon snack paired with coffee or tea.