Sift the flour and salt together in a mixing bowl and add the yeast, oil and water. Mix everything together with a wooden spoon, then use your hands to draw the mixture together into a firm dough. If the mixture is too dry to come together, add a little more water. If the mixture sticks to your hands, add some more flour.
Turn the dough out on to a well-floured surface and knead thoroughly for at least 5 minutes, then divide it into 8 equal pieces and knead into balls. Make a pointy snout at one end of each ball and place on a baking sheet lined with nonstick baking paper. Leave plenty of space between the rolls as they will double in size. Make prickles on the monsters by snipping into the dough with the tips of scissors. Press the currant halves into the dough to make the eyes and mouths.
Cover the rolls with a clean tea towel, then leave in a warm place for 1 hour or until they have doubled in size.
Brush the rolls with the beaten egg and bake in a preheated oven, 230°C (450°F), Gas Mark 8, for 15–20 minutes. If the rolls are cooked, they will sound hollow when tapped on the bottom (remember to pick them up with oven gloves as they will be hot). Transfer to a wire rack to cool.