Instructions

1. 1

   Preheat oven to 250 degrees F.

2. 2

   Heat beans in a pot over medium-low heat, just until warm.In a small saute pan, add enough oil so that there is a 1/2 to 1-inch deep layer.

3. 3

   Heat oil over medium-high heat until very hot. In the meantime, prepare lettuce, tomato, and avacado; stir about 1/4 tsp of lime zest into sour cream and add enough lime juice to thin sour cream into a "pourable" consistancy; and line a plate with a few paper towels. Test oil by placing a small edge of a tortilla into oil; if it bubbles rapidly, the oil is hot enough.Once oil is ready, dip a tortilla into the oil using a pair of tongs, and holding it into the oil, let it cook until lightly browned, 30 seconds to 1 minute. Flip tortilla over and fry on the other side.

4. 4

   Remove tortilla with tongs, letting excess oil drip back into the pan, then place on paper towels to soak up any extra oil.

5. 5

   Place cooked tortilla on a sheet pan and into the pre-heated oven to keep warm while frying the other tortillas. Repeat for all tortillas.Once all tortillas are browned, remove from oven and assemble tostada.

6. 6

   Place about 1/4 c warm refried beans on each tortilla. Top with lettuce, tomato, avacado, and sour cream-lime mixture.