Coat 9 cups of a muffin tin with cooking spray.
Heat the cream cheese in the microwave in 10-second bursts until softened and melted but not steaming. Stir in the egg, olive oil, and dill until fully incorporated.
In another bowl, toss together the spinach, feta, and bacon. Add the cream cheese mixture on top and season with salt and pepper. Use a fork to blend until uniform.
Slice the pastry sheet into 9 squares. Fit the squares into the muffin tin, stretching them a bit if necessary, and press them into the bottom of each cup. Distribute the spinach mixture evenly among the cups. Gather the 4 pastry corners over the filling and pinch to seal. Brush lightly with the melted butter.
Bake at 400°F (205°C) for about 20 minutes until golden and puffed. Let rest for 10 minutes, then slide a knife around the edges to release and help remove them.