Preheat oven to 350 F. Spray a 9x13 brownie pan with non stick spray.
Combine dandelion greens, spinach, garlic and buttermilk in a food processor. Mix until greens are well ground.
Add eggs and mix until thoroughly combined.
In a large bowl, combine flour, baking soda, salt, herbs de provence and nutmeg.
Add dandelion paste and mix until thoroughly combined.
Using a rubber spatula, fold in cheese until thoroughly combined.
Add harissa until thoroughly incorporated.
Transfer to prepared pan. Spread batter in an even layer in the pan.
Sprinkle breadcrumbs on top.
Transfer to oven and bake for 30 minutes.
Leave to cool for 10 minutes.
Cut in half and carefully remove from pan using a large spatula.