Coffeehouse by night, breakfast spot and deli by day, Kelly's Kitchen at the Porter Square Café & Diner - formerly Café International - offers a nice brunch at an even nicer price. The three-egg western omelet ($4.50), with ham, onion, and green pepper, is a fluffy gibbous moon so large it threatens to overwhelm the plate. You'll have the same welcome trouble with the Cambridge French Toast Special ($4.50), made with super-thick challah bread, happily free of the heaviness that so often undermines a good plate of french toast. Both come with a pile of fragrant home fries, cooked with thyme, rosemary, and parsley. The coffee board lists 10 kinds of joe from $1.25 to $2.50; tea's a good choice too, prepared from fresh, loose leaves. At lunchtime, sandwiches - designed for vegetarians and carnivores alike - run from about $3.50 to $5.

Kelly's Kitchen is at the Porter Square Café & Diner, 1933 Mass Ave, Cambridge. Open Monday through Thursday, from 6 a.m. to 11 p.m.; on Friday till 1 a.m.; Saturday and Sunday from 8 a.m. to 1 p.m. Call 354-0494.

- Stephen Heuser