When it comes to Hearthstone, we can't all be innovative deck builders. Netdecking the strongest (or most fun) decks around has become a part of the game—a part it seems like Blizzard might be trying to ween players off of, as seen by the latest feature to be added. Deck Recipes will be pre-made, partially completed deck lists for each class, aimed at giving players some direction when starting to build new decks.
Each class will have three recipes, one made of only Basic and Classic cards, and two made with more advanced cards and combos in mind that will change over time as sets rotate in and out of the Standard format. The Deck Recipes shown so far tend to follow themes—like Spellpower Rogue or Murloc Shaman—but aren't necessarily the best or most refined versions of those decks. I imagine that's part of the point, as Blizzard intends each recipe to be a starting point from which players can learn what does and doesn't work in their deck.
The official announcement explained that "newer players will find that the classic recipe is a great tool to get familiar with the deck-building process, but they can also serve as a handy shortcut for veteran players looking to get a new deck started." This definitely seems like the kind of tool aimed at newer players, as seen by the questionable "replace a card" feature available when you're missing one of the cards in a recipe.
As you can see from the example above, it's an imperfect system. It seems relatively easy for any experienced player, even those who never build their own decks, to see that neither Haunted Creeper nor Amani Berserker would be a good replacement for Bloodmage Thalnos in a Spellpower Rogue deck archetype. Still, it's a well-meaning feature, and I can genuinely see Deck Recipes help ease a whole new group of players into what is probably the most difficult part of any card game.
This comes on the cusp of a Hearthstone announcement (an announcement that was announced last week) and amidst rampant speculation about the theme of the next content update. It's possible Blizzard wanted to smooth out the difficulty curve of deck building in conjunction with an influx of new cards, coming changes to old cards, and the introduction of formats for the first time in the game's history. There's no ETA on Deck Recipies yet, but you can see a couple more examples below, and read the full announcement here.