Preparation Steps

• Preheat oven to 350°F and prepare a 9x13 inch cake pan with non-stick baking spray.
• Combine the flour, baking powder, baking soda, and salt in a medium bowl and set aside.
• In a large bowl, beat the butter, vegetable oil, sugar, and vanilla extract together until light and fluffy, about 2-3 minutes.
• Add eggs one at a time, mixing well after each addition. Scrape the bowl as needed to ensure even mixing.
• Add half of the dry ingredients to the wet ingredients and mix until mostly combined.
• Mix milk, half the lemon juice, and lemon zest together, then slowly add to the batter, blending well.
• Add the remaining dry ingredients to the batter and mix until smooth. Avoid over-mixing.
• Pour batter into the prepared cake pan and bake 20-25 minutes or until a toothpick inserted comes out clean.
• Remove cake from oven and poke holes all over the top using a knife sharpener or wooden spoon handle.
• Combine sweetened condensed milk with remaining lemon juice and pour over the warm cake. Let cake cool completely.
• In a large bowl, whip heavy cream, powdered sugar, and vanilla until soft peaks form.
• Add mascarpone cheese to the whipped cream and continue whipping until stiff peaks form.
• Spread or pipe the mascarpone whipped cream frosting over the cooled cake.
• Refrigerate the cake until ready to serve.