Heat the butter in a medium skillet over medium-high heat and cook the onions 8-10 minutes until golden and beginning to brown. Add the garlic and cook for another minute. Add the veggie sausage and cook for another 3-4 minutes. Sprinkle the flour over the mixture and stir to incorporate, cooking for another minute.
While stirring constantly to prevent lumps, pour in the milk and heavy cream. Stir until smooth. Add the vegetable bouillon, salt, pepper and cayenne. Bring to a simmer and stir until thickened. Add the parsley, sage and thyme and simmer for another 2 minutes. Add salt and pepper to taste.Serve immediately over the biscuits. Garnish with some additional chopped fresh parsley.