In a mixing bowl, cream together softened butter and granulated sugar until light and fluffy, about 2-3 minutes. Gradually incorporate all-purpose flour and a pinch of salt until a cohesive dough forms. Wrap in plastic wrap and chill for 15 minutes.

Roll out the chilled dough into a 12-inch circle, then press it into a 9-inch tart pan. Poke the bottom with a fork and preheat the oven to 350°F (175°C). Bake for 13-20 minutes until lightly golden.

In a bowl, beat together softened butter, granulated sugar, almond flour, and custard powder. Add vanilla and almond extracts, mixing until smooth and creamy for about 3-4 minutes.

Pour the frangipane into the cooled crust and arrange sliced peaches on top. Sprinkle turbinado sugar over the peaches.

Bake the tart in the preheated oven at 350°F (175°C) for 30-40 minutes until set with a slight jiggle in the center and a golden crust.

Let the tart cool in the pan for 10-15 minutes before releasing. Serve warm, at room temperature, or chilled.