Use a large cheese grater to shred the frozen butter. Alternatively, you can slice the frozen butter super thinly. Place the shredded/sliced butter in a bowl back in the freezer during the next steps.

In a large, clean bowl, mix together the flour and salt with a whisk. Add the 3 tbsp of soft butter and mix with a strong whisk or fork until it is all mixed and looks like crumbs.

Slowly add ½ cup and 1 tbsp of room-temperature water to the flour while stirring continuously. Stirring with a whisk here will be difficult, so use a wooden spoon, spatula, or your hands.

Keep mixing the dough until it is all incorporated and sticks together. This may take a little while, but just keep going. If necessary, you can add a bit more water, but as a last resort.

Flour a clean surface and dump the dough onto it. Knead with your hands until the dough is soft and there are no lumps. This will take about 5 minutes.

Shape the dough into a ball and put it in a bowl with a lid. Put it in the fridge for 15 minutes.

After 15 minutes, flour a clean surface (or use the previously floured area) and roll the dough to about ¼ inch thick. Try to roll it into an even rectangle if possible.

Get the butter from the freezer and spread half of it across the middle of the dough, leaving a few inches on two opposing edges. Put the rest of the butter back into the freezer.

Fold the edges of the dough over the butter so that the dough edges overlap. Turn the dough so the seam is vertical to you and roll out again to the same shape as before.

Add the rest of the butter in the same way and fold again in the same way. Turn and roll out, then simply fold again.

Put the dough on a baking tray and cover before placing it in the fridge to rest for at least an hour. You can repeat the rolling and folding method after an hour 2-4 more times.

Before you roll the dough out to be shaped, let it rest in the fridge for at least 30 minutes.

Preheat your oven to 400F and grease a 9-inch circular baking dish with plant butter or cooking spray.

Chop the onion and mince the garlic. Wash the potatoes (peeling is optional) and chop into small chunks. Mince the sage, rosemary, and thyme. Set aside.

Cut the pastry puff in half. Put one half back in the fridge and roll the other half out to line the inside of the baking dish. Press it down and up against the sides of the dish before trimming off the extra. Put the pan in the fridge until you are ready to use.

In a large skillet over medium-high heat, warm the oil. Toss in the onions and garlic and cook for 2 minutes or until the onion is translucent.

Add the flour, veggie broth, and soy milk. Whisk gently until combined before mixing in the frozen veggies, potato, sage, rosemary, thyme, salt, and pepper. Turn the heat down to medium-low and simmer for 10 minutes or until the sauce begins to thicken.

Pour the veggies and sauce into the prepared pan. Use the other half of pastry dough from the fridge to create the top. Roll it out and shape it over the filling. Trim the excess and press the edges together with a fork. Slice a few slits in the top.

Put the pie in the oven and bake for 45 minutes or until the top is golden brown. Let cool for a little, then serve and enjoy!