Add the oil to a large pan and heat to medium-high. Salt and pepper the pork on both sides to taste and sear the pork tenderloin on both sides for 2-3 minutes each side.

Meanwhile, spray the crockpot with nonstick spray or line your crockpot with a crockpot liner.

Add the sliced onions to the bottom of the crockpot, add the carrots and potatoes on top of the onions. Remove the pork from the pan and set the pork on top of the potatoes along with the bay leaves, chicken broth and garlic powder and rosemary. Cover and cook on low 5-6 hours or on high for 3 hours.

When it’s finished, strain the broth and add to saucepan. In a small bowl whisk together the cornstarch and water and add to the broth. Add more salt and pepper to taste and 1 tablespoon of stone ground mustard. Cook the broth over medium high heat, whisking constantly until thickened for gravy.

Serve with the carrots and potatoes from the crockpot and the gravy.