I made this recipe as stated (except for reducing the oil by half) and found that the batter was quite thick which I don't think had anything to do with the lesser addition of oil. I made the recipe using yoghurt. I was tempted to add some milk but decided not to. I would recommend that you either use the buttermilk suggestion or yogurt some milk, because the muffins did not 'spread out'. Also - I would recommend that you crumble the feta cheese instead of dicing because the cheese did not melt in the muffins. I don't mind that because I like my feta A LOT. All in all a nice tasting muffin that would be even better with a few tweaks.
I LOVED these! I used my scale, yet wonder if I measured everything correctly because my batter was so thick that I needed to thin it with a splash of milk. Next time I'll add more garlic powder, or scallions, or both! I crumbled the feta and used fresh rosemary ~ I got 24 mini muffins and 9 little bundt-shaped muffins. Made for Mardi Gras Photo Tag 2012.