Preheat oven: Preheat oven to 180°C/350°F (160°C fan) for 20 minutes before starting the batter. Place one shelf in the middle of the oven and a second beneath it.

Cake pans: Grease 3 x 20cm / 8” cake pans with butter and line with parchment / baking paper. (Note 9 more pan sizes)

Blueberries: Set aside ~1/3 of the blueberries (for scattering later). Toss the remaining blueberries in flour.

Be prepared: Have all batter ingredients measured out and ready to add in. New to baking? Read 'Tips for Success' above recipe card.

Combine dry ingredients: Whisk flour, baking powder and salt in a large bowl. Set aside.

Whisk eggs: Beat eggs for 30 seconds on speed 6 of a stand mixer fitted with a whisk attachment, or hand beater.

Add sugar, then beat: With the beater still going, pour the sugar in over 45 seconds. Then beat for 7 minutes on speed 8, or until tripled in volume and white.

Gently add flour: Scatter 1/3 flour across surface of whipped eggs, then beat on Speed 1 for 5 seconds. Add half remaining flour, mix on Speed 1 for 5 sec. Add remaining flour, then mix on Speed 1 for 5 - 10 sec until the flour is just mixed in. Once you can’t see flour, stop straight away.

Whisk wet ingredients: Put sour cream, hot butter, oil, vanilla and lemon zest into the now-empty flour bowl. Whisk well until smooth.

'Temper' sour cream mix: Add about 1 1/2 cups of the egg mixture into the sour cream bowl (2 big scoops, no need to be accurate). Whisk well until smooth.

Slowly combine sour cream mix and egg mix: Turn beater back on Speed 1 then scrape the sour cream mixture into the egg mixture over 15 seconds, then turn beater off.

Scrape and final mix: Scrape down sides and base of bowl. Beat on Speed 1 for 10 seconds. The batter should be thick but soft, not runny and thin.

Blueberries: Quickly but gently fold in flour coated blueberries.

Divide batter between cake pans, smooth the surface. Scatter over reserved blueberries.

Bake 25 minutes or until golden and toothpick inserted into centre comes out clean. (If you cannot fit all pans on one shelf, put 2 pans in the middle shelf and 1 pan underneath. Take the top pans out at 25 minutes, move the lower pan to middle shelf and bake for a further 3 minutes)

Once out of oven, cool in cake pans for 15 minutes, then gently turn out onto cooling racks upside down. Peel off baking paper and cool upside down - any slight dome will flatten perfectly (for neat layers).

Frost upside down layers with Cream Cheese Frosting! Decorate with extra blueberries, lemon slices and edible flowers, if desired.

Beat butter with whisk attachment in stand mixer for 2 minutes until fluffy and creamy, and it becomes a paler colour. Add cream cheese, then beat for 30 seconds just until smooth.

Add icing sugar / powdered sugar, then gently mix on speed 1 (to avoid an icing powder storm). If you do get a powder storm, cover with tea towel, then once mostly incorporated, beat on high for a full 2 minutes on Speed 7.

Add vanilla and lemon juice, then beat for a further 30 seconds. Use immediately. (Note 11 re: frosting too sloppy)