Peel 1.5 pounds (of your 2 lbs.) of your yukon golds. Set aside. Chop your veggies to get everything prepped (onion, carrots, garlic) set aside. In a large pot, submerge peeled potatoes in cold water with 1/2 tbsp of salt. Cover and bring to a boil.
In a separate large pot, add in your meat and mince it til ground. Add in a hefty pinch of salt and pepper to taste. Saute for 3 minutes and add in chopped onions. Saute until fragrant, about 3 minutes. Add in garlic, potatoes, and carrots. Saute for a few minutes.
Add in your herbs - dried sage, died rosemary, dried thyme, and ground mustard, stir to coat your veggies and meat.
Add in 5 cups of beef broth, 3 tbsp of Worcestershire sauce, and tomato paste. Stir well. For the last cup of broth, add to a small bowl with 1/4 cup flour and mix WELL to create a slurry. Bring your soup up to a light boil (boil for 10 minutes) and then add in your slurry. Add in your frozen peas and frozen corn. Continue to keep soup boiling for another 10 minutes.
Check the doneness of your potatoes (you should be able to put a fork through them). Strain the potatoes and using a potato ricer, mash your potatoes into a large bowl. In the same pot your potatoes were boiling in, put back on the stove on medium heat. Melt 2 tbsp of butter, add in 1/4 cup heavy cream, 1/2 tsp salt, 1/4 tsp white pepper (can use black pepper too), and 1/2 tsp garlic powder. Mix well.
Preheat your oven to 425 degrees. On a greased baking sheet, pipe your potatoes (using an icing piper or create your own with a plastic baggy) onto the baking sheet into little balls, spray the tops with cooking spray and bake for 15 minutes. At the very end, broil for 2-3 minutes to get golden brown (keep an eye on these as every oven is different).
This part is definitely optional, you can just add shredded cheese if that's your vibe, it'll save time also! But if you want the cheese crisps, this part is super easy. To a large skillet on medium heat with cooking spray, add shredded cheese to the pan in small circles. Let it sizzle and brown and then flip to fry the other side, flip again if needed. Remove from pan and set on a cooling rack to crisp up.
Serve your soup with the potato pillows on top, cheese crisps on the side for dipping, and chopped parsley! Enjoy!