Skin and wash the potatoes. Depending on the size you may want to halve or quarter them. But make sure to cut them into equal sizes. Add the potatoes to a pot of cold water, making sure the water is just covering them. Add in a few big pinches of salt and the crushed garlic.
Add to stovetop and bring to a boil. Reduce heat to a heavy simmer and cook until fork tender, about 10 minutes or so. Drain the cooked potatoes and then return them to the pot and cook on low to get rid of any excess moisture.
Mash the potatoes (ideally with a POTATO RICER) don't discard the garlic, it will be cooked down enough that it'll be smooth once riced.
Add the ½ cup (1 stick) of salted vegan butter, and gently fold in. Taste and adjust for seasoning, adding more butter if you like (I added in 2 Tbsp more).
In a cast iron skillet, add the plant-based meat over medium high heat and cook until browned and no pink remains. Remove from the pan and reserve.
Add in 2 Tbsp of vegan butter and melt, then add in the mushrooms and cook for about 4-5 minutes or until they've released some moisture and have shrunk down. Then add in the carrots, celery and shallots. Cook for an additional 8 - 10 minutes or until they have softened and have a bit of color.
Add in the garlic, sage and thyme. Stir and cook for 1 minute, then add in the tomato paste and worcestershire sauce. Stir and cook for 1 minute and add in the flour. Stir and cook for another minute (there's a theme here) and then add in the red wine (you can sub with grape juice and a splash of vinegar if you don't use wine). Stir to combine and cook down the wine until it's mostly been absorbed / reduced, about 1 - 2 minutes.
Add back in the reserved meat and stir to combine. Next, pour in the vegan beef broth and stir to combine. Then add in the frozen peas and combine. Cook for a minute then remove from the heat.
Smooth out the meat filling in the cast iron with the back of a spoon, pressing down but not mashing, until it's level and compact. Then spread the mashed potatoes on top, spreading them as evenly as you can.
Use a fork to draw lines into the mashed potatoes to create a craggy texture, this will help it brown at the end when we broil the top, and create some nice crispy bits on top. Do whatever kind of design your artistic heart desires!
Add the cast iron skillet to a preheated oven at 375 F or 190 C for about 20 minutes. Then broil the top for about 3 minutes or until it's browned to your liking. Just keep an eye on it so it doesn't burn!
Now the hardest part of the recipe, you need to let it rest at least 20 minutes, but 30 is better. It will be way too hot to eat and it needs to set a bit too. But you can use that time to make some gravy, recipe below!
In a skillet, melt the butter, then whisk in the flour 1 Tbsp at a time. Once all flour has been whisked in, cook for one minute to get rid of the raw flour.
Dissolve mushroom seasoning into the vegan beef / veggie broth. Whisk in the broth about ½ cup at a time.
Whisk to combine and then reduce to desired consistency (although for me the consistency was great out of the gate). Taste and adjust for seasoning.