Beef and Caramelized Onion Knishes

Ingredients

• 2 cups precooked beef such as shredded beef or beef sausage
• 1 tablespoon butter
• 2 cups sliced leeks
• 1/2 teaspoon salt
• 1/2 teaspoon pepper
• 1 cup mashed potatoes, such as Yukon Gold
• 4 ounces reduced-fat cream cheese
• 12 frozen dinner rolls
• 1 egg, beaten

Toppings:

• 1 teaspoon each: sesame seeds, poppy seeds, dried onions