Melt butter, mix in sugar, then egg, then everything else. Press 1 3/4 cups into 20cm/8" lined pan. Toss mango filling ingredients, spread on base, crumble over remaining mixture. Bake 30 min. Cool, drizzle with glaze.

Preheat oven to 180°C/350°F (160°C fan-forced). Grease then line a 20cm/8" panwith baking paper (parchment), ensuring you have overhang so you can lift it out at the end.

Melt butter - Cut the butter into ~1.25cm/1/2" chunks and melt in a microwave-proof bowl, or use a saucepan and stove. (Note 6)

Mix - Add the sugar to the butter and mix with a wooden spoon. Add egg and mix until smooth. Add remaining ingredients and mix until you no longer see flour.

Base - Measure out 1 3/4 cups (packed) of the mixture (the rest gets used for the topping). Spread into the pan and use your hands to evenly press it into the base.

Mango filling (do this just before use) - Put the mango in a bowl. Sprinkle over the sugar and cornflour. Use your hands to gently toss until evenly coated.

Assemble - Spread the mango evenly across the base. Crumble the remaining mixture across the surface, leaving spots of mango exposed.

Bake for 30 minutes until the surface is light golden.

Cool - Remove from the oven and fully cool in the pan (~ 2 hours) before lifting out using the excess paper onto a cutting board. (Speed things up: 30 min counter, 30 minute fridge).

Lime glaze - Mix the ingredients in a medium bowl, using extra lime juice 1/4 tsp at a time if needed until it's a honey consistency. Drizzle randomly across the surface. Leave for 10 minutes to let the glaze surface crust.

Serve - Cut into 12 squares (sensible) or 9 (greedy). Devour!