Line an 8×8 baking pan that fits your air fryer with parchment paper and lightly coat with baking spray.
In a bowl, mix the strawberry cake mix, vegetable oil, and eggs until just combined. Fold in the white chocolate chips [and diced fresh strawberries, if using].
Press the batter evenly into the pan with a rubber spatula. Set the air fryer to 320°F on the air-fry setting and cook 15–25 minutes, until the edges are set and a toothpick inserted in the center comes out with just a few moist crumbs.
Let the blondies cool in the pan at least 15–20 minutes before glazing — glazing warm blondies makes a runny mess.
Make the glaze: whisk the powdered sugar, heavy cream, and vanilla until smooth and thick enough to pour but not run off. Add cream a few drops at a time if too thick.
Pour or drizzle the glaze over the cooled blondies, let it set, then slice into squares, serve, and enjoy.