Heat oven to 180C/160C fan/gas 4. Mix the butter and garlic together, then use a little to grease a shallow baking dish or tin. Use the rest to butter the bread slices, then cut them in half diagonally.
Arrange the bread slices, overlapping, in the baking dish. Tuck the cherry tomatoes and ham in and around them.
Whisk the milk and eggs together, and season with salt and pepper. Pour over the bread and gently push the slices down in the liquid. Leave to stand for 5 mins. Scatter the cheese over the top, then bake for 35-40 mins until golden and just set. Serve with a crisp green salad.