Vegan Rhubarb Cinnamon Streusel Muffins

Bring water and flax seeds to a boil in a saucepan. Reduce heat and simmer for 30 minutes. Strain mixture to remove seeds. Allow to cool to lukewarm.

Preheat the oven to 350 degrees F (175 degrees C). Line 18 muffin cups with paper liners.

Mix soy milk and lemon juice together in a small bowl. Set aside until curdled, about 5 minutes.

Combine flour, baking soda, and salt together in a large bowl.

Blend brown sugar and oil in a separate bowl. Whisk in 1/2 cup flax egg mixture, curdled soy milk, and vanilla extract. Stir sugar mixture and rhubarb into the flour mixture until flour is just incorporated.

Spoon batter into the prepared muffin cups, filling each 3/4 full. Mix brown sugar, vegan margarine, and cinnamon together to make streusel topping. Spoon a little streusel topping over each muffin.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 20 to 25 minutes. Let cool in the pans for 10 minutes before removing to a wire rack to cool completely.