I've been making my chocolate chip cake from scratch for 35 years, and it's always been great. Lately, it's not rising. What's the problem? The oven has a stand-alone thermometer (350°F). The cake tins are new, professional non-stick which I grease (butter) and flour. My old tins are professional, not non-stick, and I grease and flour them. I cleaned them with SOS for years. The baking powder is brand-new. Could over-beating be a problem? Can you think of anything that could cause this problem? I've also had the exact same problem lately with my genoise (no baking powder, just separated eggs).