Cheesy Sauerkraut Pierogi - Libby's Vegetables

Ingredients

• 2 cups all-purpose flour
• 2 tsp salt
• 1/2 cup sour cream or plain greek yogurt
• 1 large egg
• 4 tbsp softened butter
• 4 russet potatoes, peeled and boiled
• 4 links of sweet sausage
• 3 cloves garlic, minced
• 1 can (14.5 oz) Libby's Crispy Sauerkraut, drained
• 1 tsp pepper
• 1 cup shredded cheddar cheese
• 2 tbsp olive oil
• 1 sweet onion, sliced
• chives (for serving)
• sour cream (for serving)