1. Preheat oven to 375°F (190°C).

2. Prepare the salmon: Drain the canned salmon and flake it with a fork. Carefully pick out and discard as many bones as possible. Save the liquid to add to the filling mixture later.

3. Microwave potatoes: Place diced potatoes in a microwave-safe bowl with 2 tbsp water. Cover and microwave on high for 5-7 minutes, stirring halfway, until tender. Drain and rice half of the potatoes, leaving half cubed.

4. In a cast iron skillet, melt the butter and sauté onions for 3 minutes until they begin to soften.

5. Add the garlic and anchovy paste and Herbes de Provence. Cook for an additional 45 seconds to bloom the flavors.

6. Stir in the flaked salmon and the mixed peppercorn medley. Cook for a few minutes to let the flavors meld before adding the salmon liquid, potatoes, and milk.

7. Gently stir in the cubed and riced potatoes, liquid from the salmon can, and milk. Taste and adjust for salt.

8. Let the filling cool for 10-15 minutes.

9. Fill one pie crust with the mixture.

10. Decorate the crust: After placing the second crust on top and trimming the excess, crimp the edges to seal. Roll out the extra dough and use it to cut out fish or underwater-themed decorations. Use cookie cutters and metal drinking straws to make shapes and poke holes for venting and create bubble-like circles as part of the decoration.

11. Brush egg wash onto all parts of crust.

12. Bake for 45-50 minutes until the crust is golden brown.

13. Cool for 10 minutes before serving.