Begin by washing and chopping the rhubarb into small, bite-sized pieces, about 1 inch long. Mince the garlic and red chili, adjusting the chili quantity based on your preferred spice level. Gather your ingredients.

In a slow cooker, combine the chopped rhubarb, minced garlic, red chili, sugar, honey, salt, cider vinegar, water, lemon zest, and lemon juice. Stir the mixture well.

Set your slow cooker to low heat and cook the mixture for 4 to 6 hours, stirring occasionally. Check for a glossy, jam-like texture.

Once the jam reaches your desired consistency, consider using a handheld blender for a smoother texture, blending carefully to maintain some chunkiness.

Transfer the jam to a clean, airtight glass jar and allow it to cool completely before sealing. Store in the fridge for up to 3 weeks.