In a dry skillet over medium heat, toast the whole peppercorns for 1-2 minutes until fragrant. Transfer to a mortar and pestle or cutting board and coarsely crush.

In the same skillet, melt butter and olive oil. Add the minced shallot and cook for 3-4 minutes until softened. Stir in the garlic and crushed peppercorns and cook for 1 more minute.

Pour in the brandy, scraping the bottom of the pan to release any browned bits. Cook until the liquid has reduced by half.

Whisk in the beef broth and Dijon mustard. Bring to a simmer and cook for 5-7 minutes, until the sauce begins to thicken.

Reduce heat to low and slowly whisk in the heavy cream. Heat gently until warmed through, but do not boil. Season with salt to taste and serve immediately.