Solar shades with simple metal valance.

Wood floor? or other....

As for how many, either one wide shade or three, but not two.

Here are more pictures. Hopefully they upload.

Pretty kitchen!

Do you actually need to be able to close the shade for privacy or bright sun? If not, consider a faux Roman Shade (not a valance).

or if you need a working treatment, do One Roman Shade that spans the whole window width. Are there any fabrics in the adjoining rooms that you need to coordinate with?

I agree with Maddielee. Look for tones that are not bright to coordinate with the surrounding room or rooms. I would go towards a light muted tone my self. Well, actually, if I had that kitchen I would not put up anything. It's beautiful by itself.

I like the window bare.

I like the window bare too, beautiful kitchen!

Betsy your kitchen is beautiful! I like how D Nelsmama did her kitchen window! I would do something like that but maybe with a white instead of natural color. Or a stationary Roman shade. The granite you have is beautiful too, I would have thought it was quartzite.

Following

Instead of "curtains", choose both mini-blinds (without strings) that you can hang within the window frame with the top of the mini-blinds and the sides of the windows covered by a long sided swag.

https://www.houzz.com/products/curtains/?productId=51895807&redirect=-1&m_refid=PLA_HZ_51895807_1587500764&device=c&nw=g&gclid=EAIaIQobChMIiayDhbzl5AIVhp-fCh1nKgrIEAkYEyABEgLI6PD_BwE

I would do one shade for all three windows. For fabric, take a look at Tonic Living. They have a nice selection of MCM inspired patterns and motifs.

Tonic Living

I like this mud-cloth style for your kitchen with it's simple pattern and warmer colors.

As mentioned you'll want to take into consideration colors/patterns you have in the adjacent room as the kitchen looks semi-open,

As for the magenta accent in the granite, I might nod to it with easily swapped out items such as flowers, pottery and the like.

To be a blend-in, white or grey? Tie Up Shade for Small Window (42" W X 63" L). Not fluffed and ruffley, so seems contemporary more so.

Soho Single Rod Pocket Blackout Curtain, White · More Info

https://www.houzz.com/products/soho-single-rod-pocket-blackout-curtain-white-prvw-vr~103592881

Soho Single Rod Pocket Blackout Curtain, Gray · More Info

I personally would want to keep all the natural daylight and not cover the window. But, if you wanted to keep the sun out or for privacy a cellular blind would work.
They are clean looking and work with any decor and can be pushed up and become invisible if you wish.

Thanks for all the feedback everyone! I like the window bare, too, but the window faces the main, somewhat busy street, so we need to cover it for privacy. We'd be ok with only covering the bottom 2/3 and leave the top open.

Being that everything is hard surface, I like the suggestion of having a more natural fabric. We do have a wood table at the other end of the kitchen, but I'd like to bring some of that element in on this part of the kitchen as well.

The walls are a light gray with white trim. The opposite wall is all glass with dark gray curtains. This window cannot be seen when standing in the livingroom, so I don't think I need to worry about tying into other materials.

Keep the suggestions coming...I really appreciate them!

Just a mention that if it'd work - outside mount could be hung high [and covering a bit of tile above] - for a neat and trim look of the whole area.

Maybe this will help you out.

Spicewood Kitchen Remodel · More Info

Spicewood Kitchen Remodel · More Info

Your opposite wall is all window/doors? then your first fabric of neutrals might be fine, and without an accent color to brighten. Do you use a color though that could be in the curtain? Tile has busyness to it, some.... and so maybe an abstract of watercolor type instead?

I don't mind valances in a kitchen especially. This is more woven in, than a pattern. Gauzy maybe - could hang so tile shows uniformly around it?

SEACOAST 45x15 VALANCE w/HT · More Info

https://www.houzz.com/products/seacoast-valance-prvw-vr~43343010

I'd try this cutey - if lightweight enough, a press-on product with tiniest of rods-

Solid Pattern Luxury Soho Straight Valance, White, 70"x17" · More Info

https://www.houzz.com/products/solid-pattern-luxury-soho-straight-valance-white-70x17-prvw-vr~92280658

Again I don't mind valances, to soften. Whatever accent color is around buy and try...

Nelson Window Curtains, Rust, 58x13 · More Info

https://www.houzz.com/products/nelson-window-curtains-rust-58x13-prvw-vr~134532149