Preheat your oven to 350°F (175°C). Grease three 5-inch cake pans and line with parchment paper.
In a large mixing bowl, cream together the butter and sugar until light and fluffy. Add the vegetable oil and mix until well combined.
Beat in the eggs, one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract.
In a separate bowl, combine the flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, alternating with the Greek yogurt and milk. Begin and end with the dry ingredients. Mix until just combined; do not overmix.
Divide the batter into two equal portions. To one portion, add red food colouring and mix until the desired colour is achieved.
Spoon the batters into the prepared cake pans, alternating between the plain batter and the red-coloured batter, creating layers.
Tap the pans gently on the counter to level the batter and remove air bubbles.
Bake in the preheated oven for about 30-36 minutes or until a toothpick inserted into the centre of the cakes comes out clean.
Remove the cakes from the oven and let them cool in the pans for 10 minutes before transferring them to a wire rack to cool completely, or wrapping in plastic wrap to freeze.