Cornetti al cioccolato e banana

Leaks usually happen when the banana slices sit too close to the edges or the bottom tip isn't pressed down firmly. Keep the banana and chocolate flakes on the lower third with a clear border of dough all around, then fold the tip over and seal it well before rolling. Cutting the slits only into the upper part of the triangle also matters - slits too far down open right over the filling.

Chopped chocolate, chocolate chips or a thick nut-chocolate spread all work in place of the flakes, as long as you stay near 1 tsp per crescent so the filling doesn't overflow. Instead of banana you can use thin apple or pear slices, though they stay firmer than banana after 20-25 minutes in the oven. If you skip the nut topping, brush with egg yolk anyway - that's what gives the golden colour.

Keep them at room temperature in a loosely covered container or under a tea towel; an airtight box traps steam and softens the puff pastry. They are at their best the day they're baked, since the banana keeps the inside moist. To refresh them the next day, warm them briefly in the oven - but do that before the chocolate drizzle and powdered sugar if you can, as both will melt.

You can cut the triangles and even shape the filled crescents ahead, then keep them covered and cold on the lined baking tray until you're ready to bake. Slice the bananas at the last moment so they don't brown, and brush with egg yolk and add the nuts just before the tray goes into the oven. The chocolate drizzle and dusting come after the crescents have cooled completely anyway, so that step is naturally a later one.

The biggest one is drizzling the melted chocolate onto warm crescents - the recipe says to let them cool completely, otherwise the chocolate runs off instead of setting. Overfilling is the second: more than about 1 tsp of chocolate flakes per triangle and the seams give way. Also cut the banana in slightly thicker slices as stated, since very thin ones turn to mush during the 20-25 minute bake.