That’s not dawn phenomenon. Dawn is when your BG goes up before breakfast. To prevent the spike, take your insulin 30 minutes before eating and you also may need to decrease your insulin:carb ratio in the morning. Mine for breakfast is 1:15 but after lunch it’s 1:17. Don’t check your BG 1 hour after breakfast, your insulin activity peaks at 1.5 hours after dosing, so you’re not even on the decline yet, but if you’re spiking like that you def need to increase the time between bolus and consumption.
Also is it white bread or whole grain? If it’s white, try eating whole grain (not cheap wheat) bread like Sara Lee Multigrain for a week. It’s more expensive but I had to switch to stop the same type of spikes. The whole grain breads digest MUCH slower, resulting in a more level absorption pattern, and provide a more consistent glucose pattern. It also will keep your feeling fuller, longer because of its slower digestion.