In a large wide bowl, whisk together eggs and half-and-half until completely smooth with no streaks remaining.
Add vanilla extract, cinnamon, brown sugar, and salt to the egg mixture. Whisk until fully combined and sugar is dissolved.
Separate Hawaiian rolls into individual pieces. Using a toothpick or skewer, poke 3-4 small holes in the bottom of each roll to help custard absorb.
Working in batches of 4-6 rolls, place rolls in custard mixture and soak for 30 seconds per side. Don't oversoak or they'll become soggy.
Heat a large nonstick skillet or griddle over medium to medium-low heat. Add 2 tablespoons butter and let melt, swirling to coat pan.
Place soaked rolls in skillet, leaving space between each. Cook for 30-60 seconds per side, turning to brown all six sides (top, bottom, and four sides) until deep golden brown.
Remove cooked rolls to a plate. Add remaining 2 tablespoons butter to skillet and repeat soaking and cooking process with remaining rolls.
Serve immediately while warm. Dust with powdered sugar, drizzle with maple syrup, and top with fresh berries as desired.
