Preheat your oven to 375°F (190°C). Line two baking sheets with parchment paper.
Lay out a sheet of phyllo dough on a clean surface. Lightly brush with melted butter. Repeat with two more layers of phyllo, brushing each with butter.
Cut the stacked phyllo into 3-inch squares and place into mini muffin tins to create cups.
Fill each phyllo cup with approximately 1 teaspoon of peach preserves.
Top with a sprinkle of chopped pistachios and a light dusting of sea salt.
Bake for 12-15 minutes or until the phyllo is golden and crisp.
Allow to cool slightly before removing from the tin. Serve warm or at room temperature.
Notes
These tartlets can be prepared a few hours in advance, providing they are stored in a dry environment to keep the phyllo crisp.