Being from Texas, Whataburger is the go to. Still our fast-food favorite.
If you are in a town near the Austin area, look for a Mighty Fine Hamburgers. Made from scratch, outstanding onion rings and fries, outstanding milkshakes and homemade lemonade.
As for nostalgia, I remember Grif’s Burgers on Fredericksburg Road in San Antonio - 15 cents (bun, meat, mustard and/or mayo). With all the veggies, 25 cents. My mom would get the ones for 15 cents, bring them home, and we added our own veggies.
