Pistachio-Crusted Pork Tenderloin with Mustard Sauce

1.4 kg 680 g (each) pork tenderloin (2) 1.5 cup 225 g shelled pistachios 1 tsp 5 ml kosher salt 1 tbsp 15 ml dry mustard powder 1 tbsp 15 ml fresh thyme leaves 0.5 tsp 2.5 ml garlic powder 1 tsp 5 ml freshly ground black pepper

1 tbsp 15 ml unsalted butter 0.5 cup 120 ml shallot, finely chopped (about 1 medium) 2 2 garlic cloves, finely chopped 1 cup 250 ml chicken broth (or 1 tablespoon Better Than Bouillon with water) 0.5 tsp 2.5 ml kosher salt 0.5 tsp 2.5 ml freshly ground black pepper 2 tbsp 30 ml Dijon mustard 1 tsp 5 ml chopped fresh sage (optional) 1 cup 250 ml 15% cooking cream 0.5 tsp 2.5 ml cornstarch