In large bowl, add beans and enough water to cover beans by 3”. Cover; soak 12 hours. Drain beans, reserving soaking liquid. Add enough water to soaking liquid to make 10 cups total; transfer to large, heavy pot set over medium-high heat. Bring water to boil. Add beans; return water to boil. Reduce heat to low; simmer, covered, until beans are completely tender, about 1 hour 15 minutes. Drain beans, reserving 6 cups liquid.

Blend beans and reserved liquid in batches, until smooth. Strain bean puree through fine-mesh strainer, if desired, discarding any solids in strainer. Transfer bean puree to large, heavy saucepan set over medium-high heat. Add coconut milk, evaporated milk, sugar, cloves and cinnamon sticks; bring bean mixture to boil.

Add sweet potatoes and raisins to saucepan; return liquid to boil. Reduce heat to medium low. Simmer, stirring occasionally, until potatoes are very tender, raisins are plump and bean mixture thickens to cream soup-like consistency, about 30 minutes.

Transfer beans to large serving bowl. Serve warm or chilled. Top with milk cookies, if desired.