In a large bowl, stir together flour, baking powder, salt, and shortening.
Slowly stir in warm water and mix until dough is smooth. Cover and let rest for 20 minutes.
While dough rests, dice up strawberries and place in a serving bowl; set aside.
Add canola oil to a depth of 1-inch in a frying pan and heat to medium-high.
Roll out dough on a floured surface to ⅛-inch thickness and cut into 3-inch squares.
Fry in batches until fluffy and golden brown, flipping halfway through, around 30 seconds per side.
Drain sopapillas on paper towels, then slice open one end and stuff with diced strawberries. Serve warm or room temperature.
Alternatively, spray each dough square with canola oil and use an air fryer set to 375°F for 5 minutes. Sopapillas won’t puff up as much, but can be topped with the diced strawberries instead of stuffed.