Preheat oven to 350°F. Grease and flour a 10" bundt pan and set aside.
In a small saucepan, add the strawberries and water and bring it to a boil on medium heat. Stir it occasionally and mash the strawberries down with a spatula. Let it cook down for 5-10 minutes or until most of the water has evaporated and the strawberry puree has thickened. Pour into a small bowl and set aside to cool.
In a medium bowl, stir together the flour, baking powder, and salt. Set aside.
In a large mixing bowl, add the oil, butter, sugar, eggs, and vanilla extract. Use an electric mixer to beat for about 3 minutes on medium speed until smooth, creamy, and lighter in colour.
With the mixer on low speed, alternate mixing in ⅓ of the flour and then milk at a time. Mix until almost combined before each addition. Stop mixing when all the ingredients are almost just combined. The batter should be smooth and silky with no lumps.
Divide the batter equally into 3 bowls (2 new bowls + the current mixing bowl). There should be approximately 1400g of batter so each bowl should have about 466g of batter.
Add the strawberry purée and 1-2 drops of red gel food colouring to one bowl. Add the cocoa powder to another bowl. Stir thoroughly to mix. Leave the last bowl untouched.
Using an ice cream scooper or spoon, add the strawberry batter to your prepared bundt pan. Gently spoon the vanilla batter on top in an even layer. Finally, spoon the chocolate batter on top in an even layer.
Bake for 50-55 minutes or until a toothpick inserted in the middle comes out clean. Let cool in the bundt pan until warm to the touch before flipping over and removing the cake from the pan.
Stir together powdered sugar and milk for the glaze and pour over bundt cake when completely cooled and decorate with strawberries or enjoy the cake plain while warm.