It's my favorite restaurant in Seattle and I know we've discussed it (the search function here isn't great, though). The value is terrific--the food is delicious, well presented, ample AND I don't think anything's over $20. As already noted the menu changes but I always love the gnocchi and scallop preparations. The "small" plates are actually pretty big, nothing like the dainty little small plates you get at a lot of places. My husband and I each usually order 2 small plates (we don't share, we treat it more like a multi course meal), and we leave full. We have ordered each an appetizer, a small and a large plate to make a nice 3 course meal but that's a lot of food. They make a nice Kir Royale too. You definitely need a rez, they're very popular.
Santa was very kind to you this year. Olivar is one of my favorite Seattle restaurants due to a great combination of (1) lovely but not-to-stuffy atmosphere, (2) divine food, and (3) extremely reasonable prices.
Because the menu changes often, it's hard to recommend specific dishes. I've dined there several times and have never been disappointed. I have also never had the same dish twice.
To maximize a chow-worthy experience, I recommend you order several dishes from the small plates menu, which really aren't that small (much more generous portions than you typically see on a tapas menu). That will allow you to try the most dishes during your visit.
Please report back on your experience!
806 E Roy St, Seattle, WA 98102