Preheat oven to 400 F. Grease or line 12 muffin cups.
Combine rhubarb, sugar (regular sugar), and ¼ teaspoon of cardamom in a bowl. Let stand for approx. 15 min until the rhubarb release some juice.
In a small bowl, beat together the brown sugar, vanilla almond milk, canola oil, vanilla extract, and the one egg.
In a large bowl mix together whole wheat pastry flour, all-purpose flour, baking soda, salt, baking powder, cinnamon, and remaining cardamom.
Add chopped strawberries and the rhubarb mixture to the flour mixture. (coating the fruit with the flour mixture helps to keep the fruit from all sinking to the bottom of the muffins). Add the brown sugar mixture to the flour mixture and combine all ingredients.
Divide the batter between the prepared muffin cups.
Bake until muffins are springy to the touch, approx. 20-25 min.