Prepare Strawberry Jam: In a medium saucepan, combine fresh strawberries with granulated sugar and a splash of water. Bring to a gentle boil over medium heat, then reduce and simmer for 20–25 minutes until thickened.

Preheat Oven: Preheat your oven to 350°F (175°C) and prepare two 6-inch round cake pans by greasing and lining with parchment.

Mix Dry Ingredients: In a large bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt until lump-free.

Combine Wet Ingredients: In another bowl, mix melted butter, oil, granulated sugar, brown sugar, and eggs until creamy.

Combine Mixes: Gradually add half the dry mixture to the wet, then half the milk, folding gently. Repeat with remaining dry mixture and milk until just combined.

Bake: Pour the batter into prepared pans and bake for 40–45 minutes or until a toothpick comes out with a few moist crumbs.

Cool Cakes: After baking, let the cakes cool in the pans for 10 minutes before transferring to wire racks to cool completely.

Make Frosting: Beat softened butter until creamy, add cream cheese and mix until smooth. Gradually add powdered sugar and some cooled strawberry jam until fully combined.

Assemble Cake: Level cooled layers, slice each horizontally into two, spread jam and frosting between layers, stack, and decorate with remaining frosting and diced strawberries.