Help.... I am new to the baking world and I have attempted to make homemade classic vanilla buttercream . Each time it has came out lumpy and tasteless....yuk.... Any ideas on what I can be doing wrong.... This is the recipe I have tried....a disappointment both times

2 sticks butter, room temperature
8 cups confectioners sugar
1/2 cup milk
2 teaspoons vanilla extract

I have used this recipe before. I whip my butter all by itself first until it's fluffy and a very light yellow, sometimes this takes 3-5 minutes depending on the temp of the butter. Then I add in the vanilla, mix until it's incorporated, then I add the sugar and "milk" ( I use heavy cream ) alternately and whip until fluffy.

I use an all butter recipe with the same amount of butter but no where near that amount of powdered sugar or milk. I also beat my butter for a few minutes before adding my salt and powdered sugar. Then when looks like crumbs I add my heavy cream and vanilla and beat on high until its light and fluffy. Also I would suggest increasing the amount of vanilla. I use 1tbsp of vanilla in my buttercream and I use less sugar and heavy cream than your recipe so that could be the reason for the bland taste possibly.

Thank you folks for the suggestions.... I will definitely try it. We'll see what happens.....