Ivo's Mushroom Leek Puff Pastry Triangles

Name: Ivo's Mushroom Leek Puff Pastry Triangles
Prep time: 1 h
Cook time: 1 h
Total time: 1 h
Yield: 4
Cuisine: Global
Ingredients: 2 Tbsps butter; 1 beaten egg; 1 garlic clove, minced; 1 leek; 8 mushrooms (button or cremini); 2 Tbsps oil; 4 servings pepper; 1 sheet frozen puff pastry; 2 Tbsps grated sharp cheddar cheese (or other sharp cheese); 2 Tbsps sour cream