Cut a piece of parchment paper to fit the bottom of your air fryer basket. Trace a 6-inch circle in the center using a pencil, then flip the paper over so the pencil line faces down.

In a clean, dry glass or metal bowl, beat the egg whites on medium-high speed until soft peaks form. Gradually add the caster sugar one tablespoon at a time while continuously beating on high speed. Continue whipping for 4–5 minutes until the meringue becomes thick, glossy, and holds stiff peaks.

Sprinkle the cornstarch, white vinegar, and vanilla extract over the meringue. Gently fold the mixture using a silicone spatula just until combined—do not overmix.

Spoon the meringue onto the marked circle on your parchment paper. Use your spatula to shape it into a nest with slightly higher edges and a slight dip in the center. Carefully place the parchment into the air fryer basket.

Set the air fryer to $200^\circ\text{F}$ ($93^\circ\text{C}$) and bake for 35 minutes. Do not open the basket during cooking. Once the timer ends, turn off the air fryer and leave the basket closed for 45 minutes to let the pavlova cool slowly without cracking.

Toss sliced strawberries with 1 tbsp powdered sugar and lemon juice; let sit for 10 minutes. Whip the heavy cream and 1 tbsp powdered sugar until soft peaks form. Melt the chocolate and coconut oil in 15-second microwave bursts. Carefully transfer the cooled meringue shell to a plate, fill the center with whipped cream, top with strawberries, and drizzle with warm chocolate.