I'm trying to get the achievement for Speed Baking 3. It's tough. Is it even possible without cheating?
Yes it is. I never cheated and got most achievements. It is key to start clicking a lot! And focus on the upgrades that increase clicking power. Don't just blindly buy any upgrades but plan your upgrade path so you don't waste cookies on upgrades that won't increase your income significantly.
See also this information page for a strategy about getting the achievement.