Set a medium saucepan over medium heat, then add butter. When the butter is melted, add the liquid smoke.
Add the onion and cook for 2 minutes, until softened. Add the garlic and continue cooking for an additional 30 seconds.
Whisk in the flour (mixture will be thick). Gradually add 2 cups of the vegan beef broth, whisking continuously until smooth.
Add the Worcestershire sauce, Cajun seasoning, thyme, oregano, and black pepper. Whisk to incorporate. Reduce the heat to low.
Simmer over low heat for 5 minutes, stirring occasionally, until thickened. Adjust seasoning to taste and serve hot. (For best results, serve immediately. This gravy will thicken as it cools to room temperature. Stir in the reserved broth to thin, as needed.)