Preheat oven to 350°F. Prepare three 8 inch round pans with baker's floured spray (or grease and line with parchment rounds).

Mix together all dry ingredients (flour, sugar, baking powder, and salt) in a stand mixer with a paddle until fully combined.

In a separate medium bowl, combine non-dairy milk, oil, vanilla, and lemon juice or apple cider vinegar and stir until well mixed. Pour into dry ingredients and stir until just combined.

Stir in crushed oreos and rainbow jimmies – the I stirred as little as possible after this point, to keep the Oreo crumbs from turning my cake layers brown!

Divide batter evenly between the prepared cake pans (I find a kitchen scale helpful for this part). This guarantees your layers will bake to be the same height.

Bake for 20-28 minutes (or until a toothpick comes out clean). Allow cake layers to cool for 10-15 minutes on a wire cooling rack before removing from pans – it helps to run an offset spatula or knife around the perimeter of the pan first. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired. (This is a great time to make your frosting!)

Cream together vegan butter and vegetable shortening until well-combined. Blend in powdered sugar alternating with vanilla extract (I added half at a time) adding almond milk if needed until a smooth and spreadable consistency is reached.

Gently mix in crushed Oreos and rainbow jimmies – stir as little as possible if you want your frosting to stay light in color!

Once your cakes are cool, level them (if needed). This can be done with a cake leveler or a large serrated knife and a ruler.

Now you're ready to crumb-coat . If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake to keep crumbs out of your final layer. I usually do this with my large offset spatula.

Once your crumb coat has set (this takes about 5-10 minutes in the fridge), add your final layer of frosting and smooth. I like to use an offset spatula and bench scraper for this part. As I worked through this part I had to pull out a few larger Oreo chunks that were getting in the way of smoothing my frosting. Fill in the holes with a bit of extra frosting and keep smoothing.

Once your sides are smooth, set the cake in the fridge or freezer for 10-15 minutes to set the frosting and chill the cake so your ganache drip will set.

Meanwhile, make your ganache. Place chocolate chips in a heat-proof bowl. Stir in vegetable shortening and microwave on half power in 20-second intervals, stirring in between until fully melted and smooth.

Slowly drizzle ganache around the upper edge of your cake, pausing every inch or so to let more ganache fall in a drip down the side of the cake. Return cake to the fridge or freezer to set the drips.

Add several large frosting swirls to the top rim of the cake – I used my largest open star for this, so the Oreo chunks wouldn’t clog the piping tip.

Space Oreo cookies in between the frosting swirls, add some crushed Oreos and sprinkles to the tip and base rim of the cake – and you’re done! Enjoy!