Grease a large bowl with oil. Line a large sheet pan with paper towels.
Melt the vegetable shortening. Set aside to cool.
Add the water, yeast and sugar to the bowl of a stand mixer. Hand whisk to combine and set aside to bloom, 5 to 10 minutes.
Add the evaporated milk and egg to the bloomed yeast and whisk to combine. Add the flour and salt. Using a stand mixer with the dough hook attachment, mix on level 3/10 until thoroughly combined, about 5 minutes. Add the shortening and mix on level 5/10 until the dough is smooth, 4 to 5 minutes. The dough should be translucent when a small bit is stretched out with your fingers.
Transfer the dough into the oiled bowl with a dough scraper. Cover with plastic or a towel and set aside until it doubles in size, about 2 hours.
Heat 4 inches of oil in a large Dutch oven or deep fryer to 360 to 370 degrees F.
On a clean workspace dusted with flour, roll out the dough to a 1/4-inch thickness, dusting with flour as needed. Cut the dough into 2 1/2-inch squares. Working in batches, carefully transfer into the oil. After dropping the squares in the oil, flip after 15 seconds and continue to flip every 15 seconds for the first minute or so. This will prevent a "hump" from forming. Fry until they are golden brown and cooked through, about 2 minutes. Transfer them to the prepared sheet pan to drain. Dust generously with confectioners' sugar and serve immediately with cafe au lait if using.