Jessica Fisher's blog, Good Cheap Eats (goodcheapeats.com), has now spawned four cookbooks, the latest of which is a spin on the 30-minute meal concept.

In "Good Cheap Eats Dinner in 30 Minutes (or Less!)" (The Harvard Common Press, $17.95), Fisher shares dozens of ideas for getting dinner on the table with not much money and not much time. This pork-and-potatoes dish is a great use of pork tenderloin, and even though it calls for the more expensive shallots, you can use onions instead.

Pork Medallions with Sherried Shallot Sauce and Smashed Potatoes

Homemade spice mixes cost next to nothing to make, and here’s Fisher’s go-to blend, which she calls FishMama Spice Mix in honor of her online moniker: Combine 1 tsp. fine sea salt, 2 tsp. garlic powder, 1 tsp. dried oregano, 1 tsp. dried basil, 1 tsp. dried thyme, 1 tsp. paprika and 1 tsp. freshly ground black pepper in a small jar. That will yield about 3 Tbsp. mix, which you can store in a jar in the cupboard.

For the potatoes:

2 lb. very small red or gold potatoes, halved or quartered

1/4 cup olive oil

1/2 cup warm chicken broth, or more as needed

Fine sea salt and freshly ground black pepper

For the pork:

4 Tbsp. butter, divided

2 lb. pork tenderloin, cut into 3/4-inch-thick slices

1 Tbsp. FishMama Spice Mix

2 or 3 shallots, sliced, or 1 medium onion, sliced

1/4 cup all-purpose flour

1 1/2 cups chicken broth

1/2 cup dry sherry

Chopped fresh parsley, for garnish

Place the potatoes in a large pot of salted water and bring to a boil over high heat. Cook until tender, 15 to 20 minutes. Drain and return the potatoes to the pot.

While the potatoes boil, melt 2 tablespoons butter in a large nonstick skillet over medium-high heat. Season the pork generously with the spice mix and cook until browned on both sides, 3 to 5 minutes. Transfer to a platter and tent with foil.

To make the sauce, add the remaining 2 tablespoons butter to the skillet to melt with the pork drippings. Add the shallots and sauté until tender and lightly browned, about 5 minutes. Sprinkle the flour over all and cook, stirring, for 1 minute. Add the broth and sherry, scraping up any browned bits. Simmer until the sauce is thickened, about 5 minutes.

After the potatoes have cooked, mash them with a potato masher until more or less smooth, but still with some chunks. Stir in the olive oil. Add enough of the broth to moisten and make the potatoes a little bit creamy. Season to taste with salt and pepper.

Return the pork medallions to the sauce and let heat for a minute or two. Garnish with chopped parsley and serve with potatoes. Serves 4 to 6.

— From "Good Cheap Eats Dinner in 30 Minutes (or Less!)" by Jessica Fisher (The Harvard Common Press, $17.95)