Pre-heat the oven to 350℉. Spray a 9X9-inch square baking pan with nonstick spray. Place parchment paper on the pan's bottom and sides. Spray again.
1
Mix cream cheese, sugar, and vanilla in a medium bowl for 2 minutes on high speed.Scrape bowl and add egg. Low-speed mix until mixed. Set aside.
2
Mix flour, cocoa powder, cornstarch, and salt in a medium basin. Set aside.For 2 minutes, mix sugar, powdered sugar, eggs, and egg yolk on high.Mix in melted butter, oil, and vanilla. Low-mix until mixed. Stir dry ingredients gently.
3
Place half the brownie batter in the pan. Spread evenly. Grab a huge cookie scoop. Completely cover brownie batter with cheesecake batter. Spread dollops randomly. Top with random brownie batter dollops.
4
Stir gently with a butter knife. Avoid overswirling batters.Bake 40-50 minutes. Bake until a toothpick reveals moist crumbs. If raw batter, bake for 5 more minutes before testing.
5
cold brownies in the pan on a cooling rack until totally cold. Refrigerate for at least 3 hours. Cut 16 brownie squares.
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