Take the road to Mason less than 10 miles (so just 10 minutes) to Hill Top Cafe, a roadhouse restaurant in an old timey gas station, opened in 1981. Check it out at http://www.hilltopcafe.com/
Going there is a great experience, worth the drive from Austin or San Antonio for a dinner excursion. The owners are a former Austin musician of Greek extraction (Johnny Nicholas) and his wife, whose Cajun credentials come from the Texas-Louisiana border. The cuisines of both are evident in the excellent food. Gumbo and po' boys at lunch; flaky spanokepitas, Greek salad or steak at dinner (from Johnny's influences) or Gulf shrimp, redfish, or whateverer came on from Port Aransas that week, from Brenda's side. Open ONLY Wed- Sun (lunch and dinner) and a great New Year's Eve destination in the middle of nowhere. I don't know of a place anywhere in Texas with better atmosphere. Johnny has played with so many famous bands, like Asleep at the Wheel -- and if you're there on a weekend night, he's likely to play some piano for you. Out of stater's will be wowed. Texans who haven't been are missing out.

First, two on the east side:

Los Comales on East 7th. Very authentic, a lot like being in Mexico with lots of Spanish spoken, inexpensive; excellent enchiladas (great green sauce, as well as chipotle), caldo de pollo is excellent; fajitas, tortas, flautas and more. As many Mexican-Americans as gringos eat here. I eat lunch here often and see everything from blue collar guys in uniforms, construction workers and a well-known judge who knows his Mexican food.

Takoba also east 7th is the opposite: stylish, sleek and spare interior decor, nice tables outside too and artsy tacos. Very good too; get the soup of the day (always excellent) and the salad that comes as a side with several dishes is really nice, with mandarin orange slices. Good date place; young hipster crowd and full bar.

Now two locals favorites:

Curra's on Oltorf between Congress and I-35 is great food with some interior Mexican specialties like mole and cane guisada. Awesome caldo (remove the chipotle or it will set you on fire), excellent enchiladas (the one with poblano cream sauce is good), steak tacos with cheese and rajas... outdoor patio, locals, a lot of musicians eat there especially lunch. Parking challenge at peak hours. Full bar, known for margaritas (including an avocado one).

I agree that Maudie's is great Tex-Mex. No attempt at authentic interior Mexican cuisine here, but very very good... Local place so successful it now has several Austin locations from the funky original on Lake Austin Blvd next to Goodwill to the hacienda-looking one at Davenport Village on Loop 360 at Westlake Drive. (my favorite -- great outdoor seating). You really can't go wrong. I like the Hernandez enchiladas (add beef or chicken for more meat), the Rockin' Ruthann's, the chicken fajita tacos, and the caldo de pollo. Full bar and reasonable

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Los Comales Restaurant
2136 E 7th St, Austin, TX 78702

Hat Creek's new Westlake location (where the pink flamigos nursery was at the corner of Bee Caves and 360) is a great place for burgers with the kids. They love the outdoor deck, playground and milkshakes. They can make choices of cheeses (pepper jack is a favorite) and can customize -- or in the case of the picky ones, just have bun, meat and cheese. Grilled cheese for the really little ones. I like the turkey burger and a vegetarian friend loves the all veggie burger freshly made by a lady in Austin who makes them special for Hat Creek. The burgers are fresh ground organic beef, the buns baked fresh. This is just good food a step above fast food. Three large flat screen TVs out on the deck for football, baseball or other games. Not too pricey and really nice employees.

http://www.grovewinebar.com/home.html
The Grove is not downtown but worth a 15 minute excursion. It is on Bee Caves Rd, barely west of Loop 360. Awesome outdoor deck under a grove of old oak trees. Definitely sit outside. Huge fan in a tree above you keeps things cool in the daytime. Lovely at night. Excellent food, innovative and tasty pastas, lots of salad choices (steak and gouda is very nice, also ahi tuna, salmon, and chicken caeser. You can customize: try a medium rare salmon on the wonderful Reed's salad). The tomato shrimp bisque is exceptional, more loke a tomoto soup than a seafood one. Bruchettas, pizzas, even some panninis. The is a destination restaurant for people who like wines and wine flights at good prices. Beer and wine only. Boring old Republicans can even order a steak with potatoes and asparagus or substitute green beans (the steak comes with a delicious peppercorn cream sauce).

http://www.grovewinebar.com/home.html
The Grove is on Bee Caves Rd, barely west of Loop 360. Awesome outdoor deck under a grove of old oak trees. Dogs are ok on the decks. Excellent food, innovative and tasty pastas, lots of salad choices (steak and gouda is very nice, also ahi tuna, salmon, and chicken caeser. Try a medium rare salmon on the Reed's salad). The tomato shrimp bisque is exceptional. Bruchettas, pizzas, wines and wine flights at good prices. Beer and wine only. Boring old Republicans can even order a steak (with a bad ass peppercorn cream sauce).