Rosemary toad in the hole with onion gravy

Ingredients

• 115 gram (about ¾ cup) plain flour
• 1/2 teaspoon sea salt
• 3 free-range eggs
• 285 millilitre milk
• 4-6 sausages, (Nici used thin Italian herb beef sausages)
• sunflower oil
• small handful fresh rosemary sprigs
• Onion gravy
• 1 tablespoon olive oil
• 1 garlic clove, chopped
• 1/2 cup chopped tomatoes
• 2 tablespoon store-bought onion relish
• splash of red wine
• 1/4 teaspoon salt and a grind of black pepper