In a large saucepan over medium heat, melt 2 Tablespoons butter. Add the onion and cook for 5 minutes until softened. Add the garlic and continue to cook for 1 more minute or until fragrant.

Add the remaining 6 Tablespoons butter and flour. Cook the roux the 2 minutes or until the raw flour smell dissipates.

Add the wine and stock. Bring the gravy to a simmer, stirring occasionally.

Add the marmite and seasoning. Continue to cook the gravy until thickened. Keep warm until ready to serve.