Rinse and dry meat thoroughly then season with salt and pepper. In a large pan over high heat, brown the meat on all sides – working in batches if necessary so as not to over crowd and steam the meat – about 1 minute per side. Remove from heat and transfer to a plate.
In the same pan over medium heat, melt 2 tablespoons butter. Add the chopped shallots, thyme and garlic and cook until tender, 3 to 5 minutes. Deglaze the pan by adding the broth and then the cognac; scrape the bottom of the pan to release the browned bits. Simmer and reduce the liquid by half, about 10 minutes.
While the sauce is reducing, bring a pot of water to a boil. When it comes to a boil, add enough salt to make the water as salty as the sea. Cook the ravioli according to package instructions.
When the sauce has reduced by half, whisk in the cream and mustard, then add the meat and any accumulated juices back into the pan. Continue to simmer over medium low heat until the meat is heated but not cooked completely through, about 2 to 3 minutes. Add the ravioli to the pan and gently stir to coat the pasta in the sauce.
If the sauce seems too little reduced, add a bit of the pasta cooking water. Stir in chopped herbs, season to taste and serve.