I need to makw lemon cupcakes. I normally use box mix and add stuff to make it taste better. What would I add to make lemon?

Duncan Hines has a lemon flavored box cake & it's pretty good  

I have tried both of these recipes with rave reviews.    Use only Duncan Hines mix for the best results.

LEMON CAKE FROM WHITE MIX (Single recipe)

1 box Duncan Hines white cake mix (16.5 oz)

1-1/2 cup all-purpose flour

1-1/8 cup granulated sugar

1/2 teaspoon baking powder

1 box Jell-O brand instant lemon pudding mix (3.4 oz.)

1/2 teaspoon salt

4 whole eggs

1-1/3 cup water

2 Tablespoon vegetable oil

1 cup (8 oz) sour cream

1 teaspoon clear vanilla flavor

2 teaspoon lemon extract

Zest and juice from 2 large lemons

Mix all ingredients for 2 minutes. Scrape bowl and mix for an additional minute. Bake in a 325 degree oven. Cake is done when a toothpick has some crumbs clinging to it.

Here is another doctored mix using Duncan Hines Lemon Cake Mix that is also excellent:

Single Recipe:

1 box Duncan Hines Lemon cake mix (16.5 oz.)

1/2 cup flour

1/8 cup sugar

1/2 teaspoon baking powder

Lemon instant pudding, 4 oz. (1 box)

1 cup lemonade

4 large eggs

1/3 cup oil

1 Tablespoon poppy seed(Optional)

What flavor of icing you would suggest 

I use the second recipe that Apti posted and get rave reviews.  No one can tell it's a boxed mix.  And I use cream cheese buttercream or lemon buttercream with mine a lot.  

raspberry icing on lemon cake is an awesome combo!

@mrsmith2 ~~Frosting depends on how fancy you want to get for your lemon cupcakes.   For a group that includes children, KEEP IT SIMPLE and use regular, unflavored buttercream with or without sprinkles.  For a group of adults with a larger tolerance for different flavor profiles and flavor combinations, the raspberry buttercream mentioned above is wonderful.

I use Bunnywoman's Mock Shack buttercream (after trying and taste-testing with about 20 people) as my go-to buttercream.  Bunny's Mock Shack is fabulous as made in the recipe below, or you can flavor it with CK Icing Fruits, Lorann Flavorings, Watkins extracts, etc. to get any flavor you want.   This frosting also takes color very well and looks beautiful on lemon cupcakes if you stripe the bag with white/yellow and use a 1M swirl.

MOCK SHACK CRUSTING BUTTERCREAM

2 cups hi ratio shortening
2 cups unsalted butter....softened to room temp!
1 TBSP vanilla flavoring
1 TBSP almond flavoring
1 TBSP butter flavoring
1/3 cup extra rich dry coffee creamer
1/3 cup boiling water
1 teaspoon popcorn salt
4 pounds pure cane powdered sugar

Place softened butter and shortening into your mixing bowl and beat with the paddle attachment for about 7-8 minutes until it has lightened in color and is nice and creamy in texture. (I use Kitchen-Aid mixer, speed 6.) This recipe nicely fits in 6 quart bowl lift KA.   It will also fit a 5 qt. KA, but it's tight.

While that is mixing, measure out 1/3 cup of water. Place this into the microwave and heat till boiling. Combine the boiling water and the 1/3 cup of dry coffee creamer. Stir until it has dissolved completely. Add in the popcorn salt to this hot liquid and stir to dissolve.
Then add liquid flavorings to the shortening/butter mixture, blend well.

Using the lowest setting on your mixer, alternate the powdered sugar and coffee creamer liquid until all is incorporated nicely. Turn the mixer up to speed 6 and beat for 8-9 minutes. The frosting will get nice and fluffy and a wonderful creamy texture.

Yield: 4 quarts (16 cups)
This crusting buttercream is not heat stable due to the butter in it.

You can mix and match up any flavorings that you like. For 4 pounds of icing, add in 4-6 drops Lorann oil flavoring and blend very well.

@Apti  the box of lemon cake I have is 15.5oz also would I make the pudding and mix it in? And the same for the lemonade? 

Yes.  The recipe above should work fine with the 15.5 oz. size.  Manufacturers are constantly lowering and re-formulating the box mixes to maximize profit.  It's very upsetting to bakers who have utilized mixes for 40-50 years because until about 2012-2013, the size of the mixes had been the same since the 1940's.     Boo hoo.....    

@Apti  should I mix the pudding with milk and add the whole box or am I adding the powder? Should I also mix the lemonade powder with water and add it?

@mrsmith2  You'll just add the powder to the mix.  I put all of my ingredients in my kitchen aid bowl all at once. mix on low just until it's all moistened, then beat on medium (4) for two minutes per mix.  (So if I'm doing two mixes, I'll beat them for four minutes.)

mrssmith2, You also asked about the lemonade. I can't imagine you would add a cup of powdered lemonade mix so I believe it means to add 1 cup liquid lemonade whether its powdered mix or frozen concentrate it should be mixed first with water, then added. If you're buying lemonade already made up then just add once cup of it. Hope this is correct!

That's right, @sparkledee3  !  Sorry I overlooked that part of her question.  Though I would recommend using fresh lemonade rather than powdered.  Powdered lemonade mixes tend to have a very artificial flavor, in my opinion.

I made them last night as a test and I think they turned out ok. I mixed the pudding And added 1 cup. I also used country time lemonade. The mix I had was Betty crocker. I plan to get different lemonade and just use the pudding powder. They turned out ok. I'm having other people test them today.

Anne Byrn, author of the 1996 Cake Mix Doctor, recommends that if adding dry instant pudding mix to a recipe to create a doctored recipe, that the baker use only Duncan Hines since both Betty Crocker and Pillsbury already have "[dry] pudding" in the mix and it may change the end result.

A "doctored cake mix" means the baker uses ONLY the dry mix that is contained in the box and does NOT follow the manufacturer's instructions for other cake ingredients.  Instead, other "doctored" ingredients provided in the "doctored mix recipe" will be used. 

Open the box of cake mix, pour dry ingredients in the mixing bowl.  Throw away cake box.  Do NOT follow any of the directions on the cake box.   Use only the dry mix that was contained in the box.

If "doctored cake mix" calls for:

Lemon (or other flavor) instant pudding mix, 3.4 oz. box - Open box, pour out powder and add to dry ingredients in the mixing bowl.  Throw away instant pudding box.  Do NOT follow any of the directions on the pudding mix box.   Do NOT make pudding and then add to dry ingredients.  Use only the dry mix that was contained in the box.

If "doctored cake mix" calls for:

Lemonade, 1 cup - Prepare a cup of lemonade that you would drink in a glass with no ice.  Instead of drinking the lemonade, add it to the wet ingredients.

You can use any lemonade that you would drink:  lemonade purchased at a convenience store, lemonade from a soda dispenser, lemonade made at home with the juice of lemons and sugar and water.