Preheat oven to 350F (180 °C). Grease 12 muffin cups or coat with cooking spray. If using frozen rhubarb, measure out 2 cups of rhubarb pieces, then finely chop. Or, measure out 2 cups fresh rhubarb cut into 1 inch pieces, then finely chop. Set aside.

In a mixing bowl, beat egg lightly. Then stir in milk, lemon juice and oil. Measure flour, sugar, rolled oats, cinnamon, baking soda and salt into a large mixing bowl. Stir with a fork until mixed, then make a well in centre. Pour in egg mixture, stirring just until combined. Gently stir in rhubarb until evenly mixed.

Immediately spoon batter into muffin cups. Bake in centre of 350F (180 °C) oven until a cake tester inserted into center of a muffin comes out clean, about 30 to 35 minutes. Remove from oven and let stand for 5 minutes. Then turn muffins out onto a cooling rack. Store muffins in a sealed bag at room temperature for up to 2 days.

Nutrients per muffin: 5.9g protein, 10.8g fat, 60.1g carbo's, 349 cals.

Baking time: 30mins