One of the things I used to be able to find in little grocery stores out in the middle of nowhere Manitoba, Canada was homemade pecan butter tarts.
They'd have a table set up near the cash register with a variety of baked goods on it that local people had made ... and most of the time those tarts were there.
SO good!
All in one heavy 800 calorie tart about the size of your fist, you've got your energy (calories), a sugar hit to get you going, fat in the tart crust, and a bit of protein from all the pecans they packed in.
Mid-ride I'd have one of those, and I would be energised for about the next 50 km!