Step 1

Preheat oven to 350 degrees F (175 degrees C).

Step 2

Heat olive oil in a large stockpot over medium heat; cook and stir stew meat until browned, 2 to 3 minutes. Add onion; cook and stir until onion is lightly browned, 3 to 4 minutes. Add potatoes, carrots, celery, and garlic; cook and stir until slightly tender, 3 to 4 minutes.

Step 3

Stir flour, butter, bay leaf, salt, and pepper into stew meat mixture; cook and stir until flour is dissolved and a gravy is forming, about 2 minutes. Pour beef stock over meat mixture, scraping brown bits of food off the bottom with a wooden spoon; cook until gravy begins to thicken, about 5 minutes.

Step 4

Mix milk and rosemary into stew meat-gravy mixture; continue cooking over low heat for 15 to 20 minutes. Stir peas into mixture.

Step 5

Pour stew meat-gravy mixture into individual pot pie pans or a 12-inch cast iron skillet; top with puff pastry, crimping the sides of the pastry down tightly. Cover with aluminum foil.

Step 6

Bake in the preheated oven until pastry is puffed and golden, 30 to 45 minutes.