Heat oil in a large, deep skillet over medium-high.
Add onion and garlic; cook, stirring often, until softened, about 5 minutes.
Add tomato paste and crushed red pepper; cook, stirring often, until tomato paste is slightly darkened in color, about 2 minutes.
Remove from heat, and add vodka to onion mixture. Stir until liquid is mostly reduced, 30 seconds to 1 minute, scraping bottom of skillet to loosen browned bits.
Return skillet to heat over medium-high; stir in butter beans, marinara sauce, heavy cream, and salt.
Bring to a simmer, stirring occasionally.
Reduce heat to medium; simmer, stirring occasionally, until sauce is slightly reduced and flavors meld, about 10 minutes.
