Shepherd's Pie with Cottage Cheese Mash

Cottage cheese mash

• 2 lb Yukon Gold potatoes, peeled and cut into 2-inch chunks905 g Yukon Gold potatoes, peeled and cut into 2-inch chunks
• 1 cup 2% cottage cheese225 g 2% cottage cheese
• 1 tbsp butter1 tbsp butter
• ¾ tsp kosher salt, plus more for the water¾ tsp kosher salt, plus more for the water
• ¼ tsp black pepper¼ tsp black pepper
• ¼ cup fresh chives, finely chopped12 g fresh chives, finely chopped

Beef filling

• 1 tbsp olive oil1 tbsp olive oil
• 2 lb 93% lean ground beef905 g 93% lean ground beef
• 1 large yellow onion, diced1 large yellow onion, diced
• 2 medium carrots, diced2 medium carrots, diced
• 2 stalks celery, diced2 stalks celery, diced
• 3 cloves garlic, minced3 cloves garlic, minced
• 2 tbsp tomato paste32 g tomato paste
• 2 tbsp all-purpose flour2 tbsp all-purpose flour
• 1 cup low-sodium beef broth235 ml low-sodium beef broth
• 2 tbsp Worcestershire sauce30 ml Worcestershire sauce
• 1 tbsp fresh thyme leaves1 tbsp fresh thyme leaves
• 1 tsp fresh rosemary, finely chopped1 tsp fresh rosemary, finely chopped
• 1 tsp kosher salt1 tsp kosher salt
• ½ tsp black pepper½ tsp black pepper
• 1 cup frozen peas135 g frozen peas

Topping

• ¼ cup grated Parmesan25 g grated Parmesan