Place beans, water, ham, onion, garlic, salt, pepper and crushed red pepper in a large Dutch oven; bring to a boil. Reduce heat and simmer, stirring occasionally, until the beans are very tender and beginning to burst, 1 1/2 to 2 hours. If necessary, add an additional 1/2 to 1 cup water while simmering to keep the beans just submerged in cooking liquid.Advertisement
Remove from the heat; discard the onion and garlic. Transfer 2 cups of the beans to a medium bowl and coarsely mash with a fork or potato masher. Return the mashed beans to the pot; stir to combine.
To make ahead: Cover and refrigerate for up to 3 days or freeze for up to 3 months.