fluffy mashed potatoes
2 tbsp. all-purpose flour
4 large carrots, cut into 1-inch pieces
8 oz. small button mushrooms
3 sprigs thyme
1 tsp. freshly ground black pepper
1 1/2 cups unsalted beef stock
2 1/2 tbsp. sweet Marsala wine, divided
2 tbsp. unsalted tomato paste
4 cloves garlic
12 oz. cipollini onions
1 tsp. kosher salt, divided
2 tbsp. canola oil, divided
2 pounds boneless chuck roast