Preheat oven to 375°F.
Beat egg whites on low speed until they begin to froth. Slowly add in ¼ cup of white sugar while continuing to beat. Turn speed to medium and beat until stiff peaks begin to form.
In a separate bowl, beat butter, remaining sugar, and egg yolks for 5 minutes until light and fluffy. Add in oil and vanilla. Add in dry ingredients, mixing until just combined. Add in champagne. Stir until cohesive.
Using a large spoon, gently fold in ⅓ of the egg whites. Once combined, fold in another ⅓ until combined. As you add in the last ⅓ of the mixture, add in sprinkles, gently folding until everything is homogenous.
Line your muffin tin, filling each liner ⅔ of the way full. Bake for 20-25 minutes until an inserted toothpick comes away clean.
Once cool, brush with champagne. Let sit at least an hour to fully absorb before frosting.