Swedish Meatballs with Mashed Potatoes and Jam

• 2 tbs breadcrumbs
• 50 ml single cream
• 1 egg
• 1 tbs Concentrated Beef Stock chicken stock could work as well
• 1/2 yellow onion finely chopped
• 25 g butter
• 500 g ground meat half pork, half beef
• 1 teaspoon freshly ground black pepper
• 1 ½ teaspoons salt
• butter for frying

For the sauce:

• 1 cup double cream
• 1 ½ teaspoon dark soy sauce
• 1 cup beef stock not concentrated
• 25 g butter
• 1 tbs corn starch or something similar, to thicken the sauce with salt and pepper
• 2 tbs lingonberry jam or cherry jam