Preheat your oven to 275°F and line a baking sheet with parchment paper. I like to trace a 9-inch circle on the parchment first — it keeps everything neat. You'll hear the oven fan kick in, which tells you it's getting ready to do its thing.

Add your 4 egg whites and pinch of salt to a super clean bowl (any grease messes everything up, trust me on this). Start beating with an electric mixer on medium-high speed until soft peaks form — this takes about 2 minutes. The whites should look foamy and fluffy, not quite stiff yet.

Gradually add the 1 cup caster sugar one tablespoon at a time while still mixing. This slow addition is what creates that glossy, dense meringue you want. Keep beating until stiff, shiny peaks form and you can't feel any sugar crystals between your fingers — about 5 to 7 minutes total.

Fold in the cornstarch, white vinegar, and vanilla powder gently using a spatula. Don't go crazy mixing — keep some air in there since that's what makes it light. I gently fold about 12 times, turning the bowl as I go, until everything's just combined.

Spoon the meringue onto your parchment circle, building up the sides slightly higher than the center. Create a little well in the middle (this is where the cream and berries'll go later). Pop it in the oven and bake for 1 hour 30 minutes until it's pale and crispy on the outside.

Turn the oven off and crack the door open about 2 inches. Let the pavlova sit in there for another 15 minutes so it cools gradually — I've had them crack when I pulled them out too fast. Once it's completely cool, carefully peel away the parchment paper.

Whip together the heavy cream, powdered sugar, and lemon juice until soft peaks form. Right before serving, pile the cream into the center, top with your mixed berries, and watch everyone's faces light up. The combination of crispy, creamy, and tart creates something really special.