Place small skillet over medium heat and add cumin seeds. Toast for 1-2 minutes moving seeds around frequently, until fragrant. Remove from heat and transfer seeds to small bowl. Set aside.
Heat butter and oil in medium saucepan over medium heat. Add chopped onions and 1/4 teaspoon salt. Cook for five minutes, stirring occasionally.
Add carrots, rice, parsley, and bay leaf to onions. Sauté for five minutes, stirring frequently.
Add 1 teaspoon of the cumin seeds, along with paprika, coriander, remaining 1/4 teaspoon salt, and freshly ground pepper to the carrot mixture. Sauté for 3 minutes, stirring frequently.
Pour broth (or water) over carrot mixture and raise heat beneath the saucepan to high. Bring to a boil, then partially cover and lower the heat to simmer. Cook for 25 minutes, stirring occasionally.
Remove saucepan from heat. Use an immersion blender to puree the carrot mixture to a texture that you like. (You can also carefully transfer the carrot mixture to a stand-alone blender and puree it that way. Make sure to leave a vent in the top for steam to escape.)
Taste to see if more salt or pepper is needed. Before serving, add the orange juice to the pureed soup and stir well. If desired, garnish each bowl with parsley and remaining whole cumin seeds.