Preheat your oven to 175°C (350°F). Grease the bottom of a 9-inch springform pan and set aside.
In a large mixing bowl, combine the yellow cake mix, eggs, melted butter, and vanilla extract. Use a spatula to stir until just combined; the batter will be thick and slightly lumpy.
Pour the batter into the prepared pan, spreading it evenly with a spatula. It should cover the bottom of the pan in an even layer.
In a separate bowl, soften the cream cheese with a spatula until smooth and creamy. Add the sugar and continue mixing until well blended.
Dollop spoonfuls of the cream cheese mixture over the cake batter, then gently swirl with a spatula to create a marbled pattern without fully mixing.
Thinly slice the strawberries and layer them evenly over the cream cheese swirls. Spoon the strawberry jam over the strawberries, letting it drip into the cracks and edges.
Use a fork or toothpick to swirl the jam and strawberries into the batter, creating a chaotic, earthquake-like marbled effect.
Sprinkle the remaining sugar evenly over the top for a slight caramelized crust.
Bake in the preheated oven for 45-50 minutes, until the crust is golden and cracked, and a toothpick inserted in the center comes out with moist crumbs.
Remove the cake from the oven and allow it to cool in the pan for at least 20 minutes. The top should be crackled and fragrant with berry aroma.
Gently run a knife around the edges before removing the sides of the springform pan. Slice and serve warm or at room temperature, enjoying the messy, juicy explosion of strawberries and jam inside.
