Almost everyone who has spent more than a week or two in San Miguel de Allende has made a side trip to the equally beautiful city of Guanajuato. Almost all of them have got there the same way. The fast way. That’s the way I got there for years.

Then one day I heard about the Santa Rosa road. It’s not really called the Santa Rosa road. But everyone seems to call it that. Officially it’s called 110. Or sometimes the Dolores Hidalgo to Guanajuato road. So why do most people call it the Santa Rosa road. It’s because about the only thing notable on the road is a town called Santa Rosa. Well that and some very, very spectacular scenery.

My first time on the road was after lunch at the highly recommended Mestizo in Guanajuato. I asked our driver to “take the Santa Rosa road back to San Miguel please”. He had never heard of it despite being born and raised in San Miguel de Allende. But, thanks to the presence of two grandaughters with iPhones and two iPhones with Google Maps, it wasn’t difficult to find. And WOW!

It was August, shortly after the rains had painted everything green and I could have sworn I was in the Swiss Alps. It was an “Is that the Matterhorn or Mont Blanc on the left” road. It was a “fasten your seatbelts” road that rises and falls, swerves left and right, rises again and swerves left and right again and again. It takes about 15 minutes longer to get to or from Guanajuato than “the fast way” but I can’t think of a more beautiful day trip from San Miguel.

Our most recent slow way to Guanajuato was with friends Charlie and Cyndy Kessler. Charlie and Cyndy have a car…actually two cars. Don Day and Don Day’s Wife have zero cars. So, when it came to choosing a place for Sunday brunch, Don Day selfishly chose a place that required a car. I sent Charlie and Cyndy a link to the website for Casa Mercedes which just happens to be on the Santa Rosa road side of Guanajuato.

“Can we take the Santa Rosa road?”, I said in a follow-up phone call.

“For sure”, said Charlie.

Highway (or perhaps it’s byway) 110 starts in Dolores Hidalgo. It takes a few kilometers before the climb starts. Then, the rolling hills slowly become mountains. And the conversation becomes gasps as the turns get tighter and eventually get down to “OMG, there aren’t any guardrails?”.

There aren’t a lot of pullovers either. There’s a restaurant called Rancho de Enmedio that’s worth a look and a beer but not much else. Then comes the town of Santa Rosa. Definitely worth a stop just to see how a town can be almost totally dedicated to one industry.

The industry is ceramics and, though the work is still very commercial, it’s a little less commercial than the shapes and patterns in Dolores Hidalgo.

A couple of twists and a few more turns later and you’re at Casa Mercedes with the town still nestled in front of you in the valley. Because the restaurant is over on the Santa Rosa side of Guanajuato, it’s not a place you’d ever accidentally find, especially if you came in or out of town “the fast way”.

The cuisine at Casa Mercedes is Mexican, very Mexican, and the owner and executive chef, Jesús Cárdenas is a walking encyclopedia of Mexican cuisine, particularly the food that originated in and around Guanajuato, the town he was born in.

Other chefs have told me about tunas, the cactus fruit known north of the border as prickly pears. I have heard about three or four different colors, heard about tastes from screw your face up sour to surprisingly sweet. Jesús Cárdenas talks about 30 different varieties, one of which he recommends for a starting cocktail “but only with mezcal made from maguey sylvestre”, the wild agave, says Jesús.

Tunas make their way not just into glasses but onto a lot of plates at Casa Mercedes as do a lot of other fruits and vegetables native to Mexico, particularly central Mexico.

A tuna with white peach flesh is served simply with chili salt.

Xoconostle, the green tuna, sides uncased sausage made with a smoked version of something else called tuna, the one that swims in the sea.

Another variety of tuna tops a crunchy corn crisp.

For a stuffed peppers appetizer, the restaurant selects local and rare caloro chiles and fills them with lamb shoulder.

And instead of using a poblano for a chile relleno, Casa Mercedes chooses the smoked version, the ancho chile.

As passionate as Jesús Cárdenas is about Mexican cuisine, he shares an equal enthusiasm for Mexican wine. Jesús innovatively puts Casa Mercedes’ wine selection not on a paper list but on a stuccoed wall where you can look, touch and make your choice.

He nodded his approval as Charlie Kessler selected an excellent Malagón Reserva de Familia, a Cabernet Sauvignon-dominated blend from the Valle de Guadalupe.

I can’t finish writing about Casa Mercedes without writing about what Jesús Cárdenas calls their “tortillas ceremoniales”. The tradition of printing an image on them before they’re grilled on the comal “goes back centuries to the local Otomi tribe”, Jesús told me.

As good as they look, just as good is the taste. The corn that’s used, an original native variety grown in the Guanajuato area, produces a tortilla that’s just far more…and sorry I can’t use another word…cornier than what’s sold at your local tortilleria.

Getting there may be half the fun but you could drive twice as far and not find a better Mexican dining experience than Casa Mercedes.

“Day trippin’ yeah!”

Casa Mercedes is located at Calle de Arriba #6 in Guanajuato, Mexico. The restaurant is open from 2:00 pm to 10:00 pm, Tuesday to Saturday; 2:00 pm to 10:00 pm, Sunday.