A shop I recommend for those who want breakfast in Karuizawa is “Kamado-cooked rice Mikuriya.”
The “Hocchi Market,” where lots of local fresh food is lined up, is also nearby, so how about visiting it as part of your morning activities?

Kamado-cooked rice Mikuriya
It’s a famous, bustling shop, but it’s a large one with parking for 20 cars and 60 seats.
If you go a little later, there are times you can get in without lining up, so do give it a try.

Terrace seats are dog-friendly.

The menu changes by time of day.

The rice is cooked using a kamado (traditional stove).

Tororo Gozen (¥1,530)
The signature “Tororo Gozen” is a set of rice, pork miso soup, grated yam (tororo), yudofu, grilled salmon, Nozawana greens with daikon, and dried daikon strips.

The tororo is seasoned with Shinshu miso. I poured it right over the rice and enjoyed it.
The interior is spacious and you can dine comfortably.
For payment, PayPay was usable in addition to cash.
A recommended shop!
For other recommended Karuizawa gourmet information, see here.
Overview
Kamado-cooked rice Mikuriya ☎0267-41-6741
Hours: 7:15–15:00 (L.O. 14:15)
Closed: no regular holiday (May–October), Wednesdays (November–April)
〒389-0113
2127 Hocchi, Karuizawa-machi, Kitasaku-gun, Nagano