Preheat the oven at 350F. Line a 9x13 Sheet Pan with a parchment paper.
Wash and rinse the raspberries. Add 2 Tbsp's all purpose flour. This step will help the berries to not settle in the bottom of the cake. and will be distributed evenly through the cake.
In a bowl sift in all the dry ingredients. Start with all purpose flour, baking powder, baking soda and salt. Keep it aside.
Now in your stand mixer bowl, or in a large bowl if you are using an electric hand mixer, add softened unsalted butter. Use the paddle attachment, and start whisking until creamy and smooth.
Now add in the sugar. Whisk again until everything is well incorporated and soft. Whisk on a medium speed.
Add in the vanilla and now start adding in 1 egg at a time. Keep whisking on low.
Now is the time to add milk and dry ingredients alternatively. We will whisk on low to make your we don't over beat the batter.
Add 1/2 Cup Milk and Half of the dry ingredients, whisk on low until well incorporated.
Now add the other 1/2 cup milk and rest of the dry ingredients. Whisk until everything is well combined.
Now scrape all the batter from the paddle attachment and sides of the bowl.
To this add orange zest and the prepared raspberries.
Incorporate them using a silicon spatula.
Don't worry, the batter for this cake is going to be thick
Now add the batter to the prepared sheet pan. Distribute it evenly throughout the pan.
Bake it for about 40-45 mins. If you think your crust is getting too brown cover it with aluminum foil. Continue baking until the skewer comes out clean.
Let the cake cool completely