To remove a coffee stain from a Basalt kitchen counter, follow these steps:

1. Blot the spill immediately with a clean and absorbent cloth.

2. Mix equal parts baking soda and water to create a paste.

3. Apply the paste to the coffee stain and let it sit for 15-20 minutes.

4. Use a soft-bristled brush to gently scrub the stain.

5. Rinse the area with warm water and dry it with a clean cloth.

6. If the stain persists, repeat the process or use a commercial stone cleaner suitable for Basalt surfaces.

Remember to clean up spills immediately to prevent stains from setting in. Avoid using abrasive cleaners or scrubbers that may damage the surface of the Basalt countertop.