Preheat your oven to 350°F (180°C) and ensure your rack is in the center position.
Combine the almond flour, coconut flour, sesame seeds, psyllium husk powder, baking powder, salt, olive oil, water, and the beaten egg in a food processor.
Process the mixture on high until the dough comes together, feels sticky, and forms a unified ball.
Line the bottom of a 10-inch (25-cm) springform pan with parchment paper to prevent sticking.
Transfer the dough to the pan and, using an oiled spatula or your hands, press the mixture evenly across the bottom to form a flat crust.
Bake the crust in the preheated oven for 10 minutes or until it is lightly browned and firm to the touch.
While the crust bakes, whisk together the mayonnaise, 3 eggs, softened cream cheese, onion powder, black pepper, and fresh dill in a large mixing bowl until smooth and well combined.
Remove the pan from the oven and spread the smoked salmon and shredded Cheddar cheese over the pre-baked crust.
Pour the egg and cream mixture over the salmon and cheese, using a spatula to smooth the top and ensure the filling is distributed evenly.
Return the pan to the oven and bake for another 30 minutes, or until the filling is set in the center and the top is golden brown.
Remove the Salmon Pie from the oven and let it cool in the pan for at least 8 minutes before slicing to allow the filling to firm up for the perfect slice.
Don't Skip the Par-Bake: Blind baking the crust for 10 minutes is crucial. This step prevents a soggy bottom by creating a firm, crisp base for the moist filling.
Let It Set Before Slicing: It's tempting to dig in right away, but letting the pie rest for at least 8-10 minutes is essential. This allows the custard to firm up, ensuring clean, beautiful slices.