Preheat oven to 400F/200C
Heat olive oil and butter in a medium-sized skillet over medium to high heat until butter is melted.
Add onion and garlic, and cook 3-4 minutes, or until onion is fragrant.
Add cumin and chilli, and stir 1 minutes.
Add diced tomato, and cook a further 2 minutes.
Combine onion, garlic, spices and cumin mix in a large bowl with the cooked shrimp, cilantro and queso fresco. Season to taste with salt and pepper and stir well.
Roll out the pie crust dough, and use a 4”/10cm ramekin, to cut circles.
Take about 1 ½ tsp of the shrimp mix, and place in the centre of dough round.
Very carefully, fold the dough in half, and seal using a fork. Gently press the fork around the edges to seal and create a pattern.
Brush with a little of the beaten egg, and place on a baking tray lined with parchment paper.
Bake in the oven for 20 minutes, until the top is starting to brown and crisp up.