Peel and cut apples into 1-inch chunks, slice rhubarb into 1/2-inch thick pieces, and hull and halve strawberries. Add all prepared fruit to a large pot along with the water and salt. This prep work ensures even cooking and helps the fruit break down uniformly during simmering.

Bring the fruit mixture to a boil over medium heat, then reduce heat and simmer for about 30 minutes, stirring occasionally, until all fruit is completely soft and breaking apart easily. The apples and rhubarb take longer to soften than strawberries, so simmering together ensures everything cooks evenly. I like to give it a stir every 10 minutes or so to prevent sticking on the bottom.

Remove the pot from heat and let cool for 2-3 minutes. Using an immersion blender, blend the cooked fruit until smooth, working in batches if using a traditional blender. For a chunkier applesauce, blend less; for silky-smooth texture, blend longer. I prefer mine completely smooth, so I blend for a full 2-3 minutes until no pulp remains.

Return the blended sauce to the stove over medium heat and simmer uncovered for 8-12 minutes, stirring frequently, until it thickens to your preferred consistency. The sauce will reduce slightly and become more concentrated in flavor. You'll know it's ready when it coats the back of a spoon and doesn't run off immediately.

Remove from heat and immediately stir in the honey, lemon juice, and ground cinnamon until fully incorporated. The residual heat will gently warm these final ingredients without cooking off the delicate flavors. Taste and adjust sweetness or tartness as needed before serving warm or at room temperature.