Whisk the milk, flour, and eggs together with a pinch of salt.
In a small baking pan, or bread tin, add a thin layer of oil (about 2 tbsp) and place in the middle shelf of your oven at about 475 F. Place something underneath to catch any oil that boils over.
Once the oil is hot, add the sausages. Cook until lightly golden.
Take the sausages out of the oven and add your batter mixture with the rosemary added in.
Carefully put the pan back in the oven for another 20 minutes or so. Remove from the oven when golden.
Fry your sliced onions and garlic in the butter for 5 minutes, or until translucent. Add your balsamic vinegar and cook down to half.
Sprinkle in your vegetable stock powder and add some water. Simmer.
Serve your toad in the hole with gravy over the top. Add a side of mashed potatoes and your preferred vegetable.
Notes
Toad in the Hole is a traditional English dish consisting of sausages in Yorkshire pudding batter, and best served in the winter for either lunch or dinner.