Add chai tea concentrate to an ice-filled glass. Pour oat milk into glass.

Top drink with nondairy apple crisp cold foam.

Mix soy milk, oat milk, apple brown sugar syrup, soy lecithin, and soy protein isolate (if using) in a mason jar and shake to combine.

For cold foam, froth the mixture until foamy using an electric frother, hand mixer, or blender.

To make apple brown sugar syrup, combine sugar, water, sliced apples, and cinnamon in a medium saucepan and bring to a boil.

Once boiling, lower heat and let simmer for 15-20 minutes, until thickened and apples have softened.

Strain mixture into a bowl, pressing down on the apples to extract juice.

Store syrup in the fridge to cool completely before using.