1. Preheat the convection oven to 350 degrees F.
2. Add all the dry ingredients into a large bowl and stir to combine. Grate the frozen butter into the dry ingredients. Add the blue cheese, spinach, parsley, and green onions.
3. Make a well in the mixture and add the eggs and half the buttermilk.
4. Fold until just holding together, adding more buttermilk as needed.
5. Line a sheet pan with parchment paper. Scoop 3-ounce portions of batter onto the paper. Bake for 22 minutes.