Preheat the oven to 175°C (347°F).
In a large bowl, add the shredded carrots, lemon juice, mascarpone and 4 spices. Mix well.
In a separate bowl, combine the instant coffee, warm water and brown sugar using the electric hand mixer until creamy and thickened. Add to the carrot mixture and combine.
Add the rice flour, baking soda and baking powder to the carrot mixture. Mix well.
Add the walnuts and mix to evenly distribute.
Grease the bottom and the top of your mini muffin tin or cupcake tray. Fill up each holder (I used about 1 1/2 tablespoons of batter in each case, filling them to the top).
Bake in the middle rack for 14 minutes. Then lower heat to 160°C (320°F) and bake for another 4 minutes. The cupcakes should be golden brown and a skewer inserted into the middle of the cake should come out clean.
Leave them to cool completely.