Crab doughnuts

Name: Crab doughnuts
Prep time: 1 h 30 min
Cook time: 15 min
Total time: 1 h 45 min
Cuisine: American
Ingredients: 2 freshly cooked crabs (or 250g white crabmeat); juice 1/2 lemon; 1 large egg yolk; ½ tsp Dijon mustard; 100ml olive oil; 1 tsp white wine vinegar; 30g butter; 75ml milk; 250g strong white bread flour; 60g golden caster sugar; 7g sachet fast-action dried yeast; 1 large egg; vegetable oil , for deep-frying; zest 1 lemon; microherbs or cress