S.S.
You can't go wrong with a flower cake for the birthday girls.
My daughter's first birthday is coming up next month. She was born on my mother's birthday. This year my parents will be here for the celebration, they live far way, so being here for a birthday is a big deal. I would like to come up with a theme that my mother and daughter can share. My mother is VERY in to birthdays being your special day...so this will be the only one where she will allow be to make it a celebration for both of them (in the future she will be upset if my daughter doesn't get her own special day). Any suggestions? This will be a smaller family gathering. The theme is mostly for the cake.
You can't go wrong with a flower cake for the birthday girls.
What about Princess Theme? You can make them both feel like real Princesses.
1st birthdays are more for adults anyway cause kids that age totally don't care. I'd say make it a bit more your mom's day with some kid stuff to make it feel like it's your daughter's day as well. Don't drive yourself crazy. It's for you and your family - your daughter'll be happy with anything :)
we did this for my youngest boy. his bday is 10 days after my mom's. so the year he turned 1, she turned 50. i wanted to do a joint party and it turned out well. we did a strawberry cake, with 2 candles, a simple meal at home with family, and it was a great time. the child got more presents of course, but she definitely appreciated the thoughtfulness.