Type 1 Spiking at breakfast regardless of what I eat?

Have you tried going without breakfast to see what happens to your BG? If you go sky high, it could be related to dawn phenomenon.
Do you take one or two basal doses? If one, maybe a split dose would be better. If two, maybe a night time reduction and morning increase is required. I think a discussion with your DSN is required.

> I thought 10g carbs spikes you roughly 3-5mmol

It is not a fixed amount. It depends on a lot of factors and can vary per person and for some it can vary depending on the time of time or depending on the type of food and/or what else is eaten at the time. Medication and stress and illness are also known to affect it.

Any chance you are sick or fighting an infection of some sort. I'm just over the flu and I had to take around double my normal Novorapid dosage (including a few meals where I took 12 units for 11g carbs!).

Would agree with dancer that it is probably best to talk to your diabetic support team.

What sort of milk do you use on your cereal ? I ask because a few months back I was having the same problem and found that using oaty milk in the morning caused me terrible spikes , I remember one morning shooting up to a bg of 19 without having anything more for breakfast but using the said milk , I cut it out and with a few other adjustments I am almost back to normal bus .

@Catsymoo sorry to read of your body's Foot On The Floor (FotF) response.
I have a few questions
- how soon after getting up do you eat breakfast? Some find that eating will slow the FotF. This does not have to be full breakfast but could be a handful of (low carb/carb free) nuts to convince your liver that you are not starving.
- how long before eating do you pre-bolus? Some people find that, because they are insulin resistant in the morning they need to pre-bolus much earlier than they do for other meals. I have read of some people pre-bolusing 45 to 60 minutes before breakfast.
- are your readings from a CGM (e.g. Libre) or are they checked with a finger prick? CGMs have a tendency to over-egg highs so it is definitely worth double checking these if you don't already. It is possible your BG dos not shoot as high as you think.
- what basal insulin do you take? You mention that your BG plummets overnight so you do not want to increase it. That suggests you are on a once a day rather than twice a day. However, your body may be needing more insulin during the day than night so a shorter long acting insulin like Levemir which you need to take twice a day may be better for you.
- when do you take your basal? If you take it in the morning, it is possible that your morning rise is compounded by your basal running out and not lasting a full 24 hours. If this is the case, you could try moving it to the evening (so it runs out when you are awake and your can top up with bolus) or splitting your dose (so it overlaps)
-do you do correction doses? If so, do you use your usual correction ratio? When our BG goes high, we become insulin resistant so we need more insulin to correct a high. For me (and his is only me - you will need to work out what it is for you(, I need 1.5 x my correction when over 12 mmol/l and 2 x my correction when over 15.

I apologise for all the questions - I guess it is the way my brain works.