Starbucks Pain au Raisin

The Starbucks Pain au Raisin costs £4.30 and carries 351 calories with 19g of sugar. Croissant dough rolled with raisins and a custard filling into a spiral.

It is the lightest pastry Starbucks sells, at 63 calories below the butter croissant and 168 below the almond croissant. Saturated fat is 10g against the croissant's 14g and the almond version's 16g. For anyone who wants something from the pastry case rather than the lightest thing on the menu, this is the one the numbers point to.

The reason is shape rather than recipe. A spiral pastry uses less dough than a rolled crescent of the same footprint, and the custard occupying the middle displaces pastry that would otherwise be more butter. Filling something with custard and ending up lighter is not intuitive, but that is what the geometry does.

Sugar is where it pays, at 19g, the highest of the four viennoiserie. Raisins and creme patissiere both carry their own, and 19g against the plain croissant's 5.4g is nearly four times as much. It is the sweetest pastry in the case by a clear margin, which matches how it tastes.

Custard is also what makes it the pastry with the shortest shelf life in the case. Creme patissiere is a fresh dairy filling and it does not keep the way chocolate or frangipane do, which is why these are baked in smaller numbers and why a store late in the day is more likely to be out of this one than any other.

The price is unusual in one respect: it is the only item on the breakfast menu with no spread at all, listed at £4.30 across every platform observed. It lists egg, barley, wheat and milk. The pain au chocolat is the less sweet filled option at 14g of sugar.