Name: Black bean and corn tostadas
Prep time: 18 min
Cook time: 15 min
Total time: 35 min
Yield: 2
Ingredients: 6 soft corn tortillas, about 15 cm / 6 inches across (150 g); 2 tsp olive oil, for brushing (9 g); 1½ cups cooked black beans, drained and rinsed (280 g); ½ cup frozen corn kernels (68 g); ¼ cup water (60 ml); 1 tsp ground cumin; ½ tsp smoked paprika; ¼ tsp fine salt, divided; 1 cup green cabbage, finely shredded (measure after shredding) (70 g); 1 medium tomato, cored and finely diced (123 g); ¼ medium yellow onion, peeled and finely diced (27½ g); 2 tbsp lime juice

These tostadas combine warm mashed black beans and sweet corn with crisp cabbage and a sharp tomato, onion and lime topping. Six small corn tortillas bake flat while the filling cooks in a saucepan. Divide the batch into two lunches of three tostadas, adding the fresh toppings just before eating.

Give the shells room to crisp

Choose soft corn tortillas about six inches across and check their combined package weight. Tiny street-taco tortillas will need smaller portions of filling. Two trays give six tortillas enough space to lie flat; overlapping edges remain soft and make awkward bases for the toppings.

The oven temperature and starting bake window follow the baked-tostada method in UC Davis’s cooking curriculum. Brush the measured oil thinly over both sides and check the tortillas individually toward the end. Thickness and moisture vary by brand. A shell should have a dry, firm center as well as a crisp edge. Let it cool uncovered before spreading the filling.

Keep the filling spreadable and the vegetables small

Weigh the beans after draining and rinsing. The quantity is cooked beans, so dry beans need cooking separately before starting this recipe. Keep the corn’s cooking water in the saucepan: it helps the beans soften into a spread without requiring more oil.

Mash most of the beans while keeping the corn largely whole. A few whole beans are fine, but a loose pile of beans and kernels can roll off the shell. Cook away any liquid that collects around the mixture. Divide it into six portions before spreading so each tostada gets an even layer without a heavy mound in the middle.

Shred the cabbage finely and cut the tomato and onion into small pieces. This makes the topping easier to distribute and bite through. Add the cabbage over the beans, then spoon the tomato mixture across the top. Lime juice and tomato juices soften a crisp shell as it sits, so assemble only the portion being eaten.

Pack the components separately

For a second lunch, refrigerate the bare shells, filling, cabbage and tomato mixture separately. The shells will soften in the refrigerator; a short spell in the oven restores their dry surface. Let the reheated shells stand briefly before handling, and keep the vegetables cold until assembly.

CDC’s food-safety guidance calls for prompt refrigeration, shallow containers, and a one-hour limit in temperatures above 90°F / 32°C instead of the usual two hours. The card uses a two-day refrigerated window. Health Canada recommends reheating leftovers to 74°C / 165°F. Stir the bean filling and check several places with a thermometer; warm edges alone do not establish the center temperature.

Storage & reheating

For lunches, keep bare shells, bean filling, cabbage and tomato topping in separate containers. Refrigerate within 2 hours (1 hour above 32°C / 90°F) at 4°C / 40°F or below; use within 2 days. Cool the filling in a shallow container and loosely cover until cold. Reheat only the filling needed to 74°C / 165°F, stirring and checking several places. Re-crisp bare shells in a 180°C / 350°F oven for about 3 to 5 minutes, watching closely. Add cold toppings just before eating.

Substitutions

Cooked, drained pinto beans can replace the black beans at the same weight; mash them to the same thick consistency. Nutrition and cost will change.
Lemon juice can replace the lime juice at the same measured amount.

Cooking notes

Makes six 15 cm / 6 inch shells; all toppings and 150 g tortillas are included. Package weights vary.
Weigh beans cooked and drained, and vegetables after trimming.
Timing assumes preheating during prep and filling cooked during baking. Extra batches or longer package cooking add time.
Original gram references: cumin 2 g, paprika 1 g, salt 1.5 g and lime juice 30 g.

Ingredient	USD	CAD
soft corn tortillas, about 15 cm / 6 inches across	$0.24	$1.39
olive oil, for brushing	$0.11	$0.11
cooked black beans, drained and rinsed	$0.90	$1.11
frozen corn kernels	$0.20	$0.31
water	$0.00	$0.00
ground cumin	$0.04	$0.11
smoked paprika	$0.04	$0.05
fine salt, divided	$0.00	$0.00
green cabbage, finely shredded	$0.16	$0.14
tomato, cored and finely diced	$0.55	$0.53
yellow onion, peeled and finely diced	$0.06	$0.06
lime juice	$0.09	$0.17
Recipe total	$2.39	$3.97
Per serving	$1.20	$1.99

Black bean and corn tostadas

Give the shells room to crisp

Keep the filling spreadable and the vegetables small

Pack the components separately