In a stand mixer, add unsalted butter, vegetable oil, and sugar. Mix until light and fluffy, about 2 minutes.
Add in eggs, vanilla, and sour cream. Mix until just combined, while making sure to scrape down the sides of the bowl.
In a separate bowl, add flour, baking soda, baking powder, and salt. Give it a quick stir, then add the dry ingredients to the wet ingredients. Mix until fully combined.
In your lined baking pan, add half of the cake batter. Using an offset spatula, spread out the batter so that it's flat and covers the bottom of the pan.
Next, take 3/4 cup of cherry jam and dollop it over the top of the cake batter. Using a knife or an offset spatula, gently spread out the jam. Then, add the remaining half of the batter over the cherry jam and spread it out. Take the chai crumble and evenly coat the top of the cake. It will seem like a lot of crumb at first, but I promise that's what you want! This will help you achieve a tall crumb, just like the New York-style crumb cakes.
Bake the crumb cake at 325°F for 55 -60 minutes . Depending on your oven, it might take less or more time but this is a thick cake so we need to make sure it bakes all the way through. If you notice the crumb on top getting too dark, cover the top of it with aluminium foil to finish baking. The crumb cake will be done once you can stick a toothpick or skewer in the middle and it comes out clean. Set aside to cool for at least 20-30 minutes before cutting. Top with a sprinkle of powdered sugar. Note: this is a thick layer of crumb and a delicate cake, when cutting make sure to use a very sharp knife.