Preheat the oven to 345° F (175° C). Place the cashews into a heatproof bowl and cover with hot boiling water. Set aside for 30 minutes.

In a large bowl, mix the oat flour, almond flour, baking soda and baking powder, ginger powder, and lemon zest.

Add the wet ingredients (yogurt, agave, lemon juice, and vanilla extract) and mix with a fork to combine and create a smooth batter. If the batter is too thick, add a splash of non-dairy milk to thin it out. Add a little at a time to reach the desired consistency.

Divide the batter into cupcake molds leaving room on top for rising, then bake for 20 minutes until set (insert a toothpick into a cupcake center; if it comes clean, they are ready).

Drain the cashews and place in the blender with the rest of the ingredients. Process to get a creamy mixture, then transfer into a bowl, cover with cling foil, and freeze for 15 minutes.

Remove from the freezer and use a hand mixer to smooth the frosting, then cover the bowl with cling foil and let rest in the freezer until ready to use.

Take the cupcakes out of the oven and set aside to cool completely into the molds, then remove them from the molds and arrange on a large plate.

Transfer the frosting to the icing bag and top the cupcakes. Serve right away.