Preheat oven to 350F. Line a 9x13-inch baking dish with parchment paper.
In a large bowl, whisk together the eggs and yogurt until smooth. Stir in the spinach and 1 cup of the cheese.
In a high-speed blender, add the oats and blend briefly into a coarse meal. Add the walnuts and pulse again until walnuts are finely chopped.
Transfer the oats/nuts into the bowl along with the spices, salt, and baking soda. Stir until combined.
Pour the mixture into the prepared baking dish and spread into an even layer. Sprinkle evenly with the remaining ½ cup cheese.
Bake for 30-35 minutes or until a knife comes out clean and the top is golden brown.
Let cool for about 10 minutes, then slice into 12 squares. Enjoy warm on its own, topped with a fried egg, or turn it into an egg sandwich!