Baking – How important is the creaming process while making a cake

What you are making is a pound cake. Or maybe a sponge cake, depends on the order of mixing the ingredients. Of the two, the sponge cake is somewhat lighter, so if you have been making pound cake (cream butter and sugar, add eggs, then flour), you can switch to sponge (foam eggs and sugar, add flour and fat). But both are hearty homemade cakes, they are supposed to be dense.

The iced cakes you get in a bakery are much lighter, because they use a different type of layer. Most types of cake are lighter than pound and sponge cakes. Try making genoise, chiffon, or angel food cake layers, they are all light. And yes, using cake flour will help too, or replacing part of the flour in the recipe with pure starch (usually cornstarch or potato starch, you can also use wheat starch if you can get it. Tapioca or arrowroot aren't that well suited). For a real "pro" taste, also throw in some lecithine, it makes the mouthfeel softer and smoother - but if you don't feel like hunting around for lecithine, don't bother, a good homemade cake doesn't really need it, I only mentioned it because you asked about "cake made by a pro".

You have three options:

1. Prepare for drippage. If you're doing a lot of small items in particular, you set up a wire rack over a sheet pan, and just let it drip down. For the small items, you can dip into the glaze, then invert and place on the rack, like you would glaze a donut.

2. Add a barrier. Make a thicker icing that won't flow, and pipe right at the edge to give it a little bit of containment, then flood the top with the thinner icing. You'll need the cake nearly level for this to work well.

3. Pipe it on. You need an icing that's just thinned to the point where it will slump and flow back together, but not so thin it'll flow off. Use a piping bag (or plastic bag with the corner cut off) to make lines close enough together so the icing forms a solid covering. You may want to start at the outer edge and make a ring like #2, then work inward. This can work for more uneven cakes, as it doesn't need to be perfectly level, but it's more effort to get the consistency right.

Exact technique and consistency is going to depend on how thick (depth) you want the icing. It's always easier to thin it (doesn't take much added liquid) than to stiffen it back up.