Preheat & Prepare
Preheat oven to 375°F (190°C).
Lightly grease a 9-inch pie dish.
Press pie crust into dish and set aside.
Cook the Mushroom Filling
Heat olive oil in a large skillet over medium heat.
Add onion and sauté 3–4 minutes until softened.
Stir in garlic and cook 30 seconds.
Add sliced mushrooms.
Cook 8–10 minutes until mushrooms release moisture and it fully evaporates.
Allow mushrooms to brown deeply for maximum flavor.
Create the Creamy Sauce
Sprinkle flour over mushroom mixture.
Stir and cook for 1 minute.
Slowly pour in plant milk while stirring continuously.
Add soy sauce, thyme, salt, and pepper.
Simmer 3–5 minutes until thickened and creamy.
Remove from heat.
Assemble the Pie
Spoon mushroom filling into prepared crust.
Smooth the top evenly.
Optional: Add top crust or decorative pastry strips.
Brush crust lightly with plant milk.
Bake
Bake 35–40 minutes until crust is golden brown.
Let cool 10–15 minutes before slicing.