Keeping batter and frosting to bake later

What I would do, make the frosting tonight - completely store in fridge.
measure out all ingredients for the cake tonight so you can whip it up quickly andn bake while you have the frosting coming up to room temp. While the cake is in the oven, rebeat the frosting.

You can make the batter, dish it out into the cupcakes papers (in the pan) and freeze (when frozen take out of pan and stack them in bags). Thaw in the fridge and bake as usual. I've done this with chocolate and cookies n' cream cupcakes.

Cake batter DOES KEEP! YOU DO NOT NEED TO BAKE ALL CAKE BATTER THE DAY IT IS MIXED.

Almost all American/Western "creaming method" cake batters can be baked up to 4 days after they've been mixed. In fact, some cakes are better made with batter made the day before! I suggest letting batter come to room temp before putting it in pan &/or baking it, although a batter can be baked right from the fridge.

Yes, you can also freeze already baked goods, but I would not suggest this unless you don't need those cakes a month from now. Home & commercial freezers can really dry out a perfectly nice cake. Baked cake DOES NOT NEED TO BE REFRIGERATED or frozen. (I keep my cakes, muffins and pies at room temp up to 3 days after I bake them, and only refrigerate if they're filled with ganache/mousse/bavarian etc.) And neither do most frostings, unless your kitchen's ambient temperature maintains at 75F+. Most buttercreams will not melt or go rancid unless something goes horribly wrong.

Some cakes get more moist when refrigerated the day they are baked (although I like to cool my cakes to room temp. before popping in fridge.)

Just bringing homemade cakes to a party is gift enough! Don't worry too much about the fact thet you didn't make, bake, frost & assemble that day!

I'd also premeasure and then dump and stir. That said, I've made cupcakes and frosting a day before I need them, kept the cupcakes wrapped tightly on the counter, frosting in refrigerator, and assembled mornig of with great success.

I often do what vvvanessa recommends: I measure out dry ingreds and sift together the night before, then put in a ziplock bag or covered in a bowl so you don't have to re-sift the next day. You can line the cupcake tins and have them ready to go. Mix liquids the next day and combine then bake. There's a little less to clean up if you've gotten the measuring and sifting out of the way.

Make the frosting the night before. You should be able to make up the cake batter in the time the oven takes to heat.

Abby Dodge Emergency Blender Cupcakes

1 cup flour
1/2 unsweetened cocoa powder (not Dutch process)
1 cup sugar
1/2 tsp baking soda
1/4 tsp salt
3/4 cup hot water
1/2 cup canola oil
1 large egg
1 1/2 tsp vanilla extract

Heat oven to 375°. Line 12 regular-sized muffin cups with paper or foil liners.

Combine flour, cocoa, sugar, baking soda, and salt in a blender. Cover with the lid and blend on medium speed until blended. Pour in the water, oil, egg, and vanilla. Cover with the lid and blend on medium-high speed until smooth and well blended, stopping to scrape down the sides once or twice. Pour into lined muffin cups, dividing evenly. Bake until a toothpick inserted in the center of one cupcake comes out clean, 17–19 minutes. Transfer to rack to cool for about 10 minutes, and then carefully remove the cupcakes from the pan and set them on the rack to cool completely before frosting.

Cake batter won't keep, but it shouldn't take long to mix, so what if you just had all your ingredients measured out and ready to go (you can probably even mix all your dry ingredients together) and just put the batter together right before baking?

You can bake the cupcakes today and freeze them to ensure freshness and thaw the day of. What kind of frosting are you making? If it's a buttercream made with butter and powdered sugar you can make that and refrigerate but let come to room temperature before icing the cupcakes. I wouldn't make cake batter and keep until Thursday,