Preheat the oven to 400°F/200°C and line a 12-hole muffin pan with paper cases.
Chop the rhubarb into ½-inch pieces and add to a pot with the sugar and water. Bring to a boil, then reduce the heat and simmer for 5 minutes or until soft. Transfer to a blender and puree.Measure out 1 cup of rhubarb puree to use in the recipe (save the remaining to swirl).
Whisk the flour, sugar, baking powder, ginger and salt in a large mixing bowl.
Add 1 cup of the rhubarb puree to a jug along with the eggs. Whisk well.
Add to the dry ingredients with the melted butter and vanilla and beat for a minute or so to combine.
Spoon the mixture into the muffin pan ¾ full, then add a small teaspoon of the leftover rhubarb puree to each muffin and swirl with a knife.
Bake for 15 minutes or until risen and an inserted toothpick comes out clean.
Allow to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
Do not overfill the muffin liners as you don’t want them to spill over while baking. Fill ¾ full.Make sure the egg and milk are at room temperature before forming the muffin batter to yield the best results in texture. Transfer to a wire rack, then cool completely before enjoying to make sure they set properly. It’s important to make sure you don’t overwork the muffin batter. Mix everything until it’s combined but not any longer. This will make sure the muffins stay light.