Heat the oven to 190 C / 375 F and have a 33 x 46 cm / 13 x 18 inch sheet pan ready. Tip the cherries into a colander, drain for 10 minutes, then pat them dry with paper towels. Melt the butter.

Warm 30 g of the melted butter in a 20 cm / 8-inch nonstick skillet over medium heat. Add the breadcrumbs and stir for 2 to 3 minutes until golden and fragrant, then tip them onto a plate. Leave the remaining 70 g butter in its bowl for brushing.

Stir the drained cherries gently with the sugar, cornstarch, lemon zest, lemon juice, cinnamon, and salt. Do this just before assembling so the sugar doesn't draw out extra juice.

Lay a 50 cm / 20-inch sheet of parchment on the counter with a long edge facing you. Place one phyllo sheet on it, brush lightly with butter, and repeat with the remaining 7 sheets, keeping the unused sheets under a damp kitchen towel.

Scatter the toasted crumbs in a strip 10 cm / 4 inches wide along the long edge nearest you, starting 5 cm / 2 inches in from the edge and leaving 4 cm / 1.5 inches clear at each end. Spoon the cherries over the crumbs. Fold the clear ends over the filling, then roll the strudel away from you, lifting with the parchment, until the seam sits underneath.

Lift the log, still on its parchment, onto the sheet pan and trim any overhang. Brush the top and sides with the remaining butter and cut 4 shallow slits across the top. Bake for 35 to 40 minutes, until deep golden brown and crisp when tapped.

Cool the strudel on the pan for 20 minutes so the filling sets. Dust with powdered sugar and slice into 8 pieces with a serrated knife, using a gentle sawing motion. Serve warm.