Whisk the flour, baking powder, and salt together in a large bowl or use a food processor. Add the cold butter and cut into the dry ingredients with a pastry cutter or pulse several times in the processor.

Cut/pulse until coarse crumbs form. Add 1 cup (240ml) milk (reserve the rest for brushing on dough in step 4), and then stir/pulse until the dough comes together. Dough will be very shaggy and a little wet.

If it’s too dry, fold in another Tablespoon of milk. If it’s too wet, fold in another Tablespoon of flour.

With generously floured hands, shape biscuit dough into 8 or 9 1-inch-thick discs. The amount of biscuits you need depends on the size and shape of the baking dish.

Place shaped biscuits on a lined plate or baking pan, cover tightly, and refrigerate until ready to use or for up to 2 days.

Melt the butter in a large skillet over medium heat. Add the onion, carrots, celery, mushrooms, and garlic. Cook, stirring occasionally, for 5 minutes until softened.

Stir in flour, salt, pepper, and thyme until flour has absorbed all the liquid. Stir in the broth and ½ cup milk.

Cook and simmer for 7–9 minutes or until thickened into a thick soup-like consistency. Stir in mixed vegetables and parsley, then remove from heat.

Taste and add more salt, pepper, thyme, or parsley if desired. Cool for 5 minutes.

Preheat oven to 400°F (204°C). Pour filling into greased 2.5- or 3-quart baking dish or 9-inch pie dish.

Arrange cold biscuits on top, brushing the tops with remaining 2 Tablespoons milk.

Bake for 25 minutes, then turn oven up to 425°F (218°C) and bake for 5–6 more minutes until biscuits are golden brown.

Remove from the oven and allow to cool for 5 minutes before serving. Leftovers keep well in the refrigerator for up to 5 days.