Preheat the oven to 180ºC, gas mark 4. Brush the 12 holes of a muffin tin with melted butter; dust each with a little flour, shaking out any excess.

Pulse the pistachios and caster sugar in a food processor until the nuts are finely ground.

Tip the ground pistachios into a mixing bowl with the flour, ground almonds, sifted icing sugar and salt.

In a separate large bowl, whisk the egg whites for about 2 minutes, until frothy and foamy.

Sift the dry ingredients over the egg whites and fold in gently until just combined.

Pour in the melted butter and stir until just combined.

Evenly spoon or pour the batter into the holes of the tin, until each is ¾ full.

Gently place a few strawberry slices on top of each and bake for 20-22 minutes, until risen and golden brown.

Cool the friands in the tin before lifting out onto a wire rack to cool completely. Dust with more icing sugar to serve.