Heat the butter in a heavy-bottomed pot. Add the onion and garlic; saute over medium heat for 5 minutes. Add the saffron, salt, and pepper; saute another minute. Stir in the rice and broth. Cover the pot and for 15 minutes. Remove the rice from the stove and allow it to rest for 5 minutes. Stir in the raisins and toast-ed almonds.