Heat a large non-stick skillet over medium-high heat and sauté the bacon until it starts to brown, stirring frequently—about 8 minutes.
Add the onion and sauté until the onion is translucent and the bacon is golden brown, stirring frequently—about 8 minutes.
Add the beef and sauté until it is cooked through and browned, stirring frequently to break up clumps—about 10 minutes.
Add the garlic, stir to incorporate fully, and sauté it until you can smell the garlic cooking, about 1-2 minutes. Remove skillet from heat and cool the beef mixture.
Flour a work surface and unroll the tubes of dough onto the surface. Separate each roll into 8 equal pieces for 24 pieces total.
Heat the oven to 375°F. Line 2 sheet pans with parchment paper. Whisk together egg yolk and 1 teaspoon of water.
Place 2 heaping tablespoons of the beef mixture at the center of a dough round. Bring together opposing sides of the dough and pinch together to form an open-ended tube. Then fold each open end towards the center and pinch the dough so it's tightly sealed, creating a pill-shaped bun. Turn it over and place it seam side down. Brush top with egg wash. Repeat with remaining dough rounds.
Cook for about 15 minutes—the buns will be light amber brown and firm to the touch. Cool for 10 minutes before eating.