Heat the griddle to low. Toast walnuts on the griddle for a few minutes until they are fragrant. (Do not add any oil to the griddle.)
Add walnuts to a blender and pulse until coarse crumbs. Add oats, maple syrup, brown sugar, red pepper flakes, sage, thyme, rosemary, nutmeg, eggs, salt & pepper. Pulse in the blender until combined.
Place egg ring molds on the griddle and spray with griddle spray. Spoon walnut mixture into molds and cook for 2-3 minutes. Remove egg ring molds and flip the patty. Cook for an additional 2-3 minutes until both sides are golden brown. Transfer to a warming rack while you cook eggs.
Scramble additional eggs on the griddle, top with cheese, and cover with a dome until the cheese has melted. Toast croissants on the griddle with butter. Cut each patty in half and assemble the sandwiches with croissants, eggs/cheese, and sausage. Enjoy!
