Science outreach programs that enable real-time interactions between scientists and school-aged children are known to positively impact learning gains and students' perceptions of scientists. To expand K-12 outreach by scientists, it is important to build structured outreach programs which offer scientists well-defined opportunities, while providing school students regular and diverse interactions. We describe Talk To A Scientist, a science outreach platform in India, where scientists use a webinar-based approach to share their research with K-12 students (6 to 16 years). Running weekly for nearly 3 years, Talk To A Scientist has hosted over 100 live interactions, with a wide reach to participants across the country. Here, we outline the framework used to build Talk To A Scientist and discuss key gains, considerations, and challenges in the development of the program. We also suggest potential adaptations with which this framework can serve as a guideline for the implementation of similar K-12 outreach programs across diverse country- and context-specific settings.