Champagne vinegar (or, alternatively, white wine vinegar)
Salt, to taste
For the hollandaise:
2 egg yolks
1/2 stick butter, melted
1 clove garlic, grated
1 lemon, juiced
Salt, to taste
To assemble:
3–4 slices sourdough, toasted
Freshly cracked black pepper, to taste
Instructions
Add all jam ingredients to a large pot and bring to a boil. Reduce to a simmer, blend with a hand blender to avoid any large segments of tomato skin, and cook until thick and jammy, about one hour. Transfer to a bowl or jar, cover and seal tightly, and refrigerate until chilled and thickened. Note: You can make this jam ahead and store it in the fridge for up to a week or use it as soon as it’s cooled.
While you wait, bring water to a boil, add salt, and blanch diced celery until bright green (it should look like sea glass) and slightly tender but still crunchy, about 1 minute. Immediately transfer to an ice bath. Drain, add to a mixing bowl, and gently toss with olive oil, vinegar, and salt. Taste and adjust as needed.
Prepare the hollandaise, if using: Over the same pot of water used for the celery, place a large bowl with egg yolks, grated garlic, and lemon juice. Slowly whisk in melted butter, until thickened, Season with salt. Taste and adjust as needed.
Build your toasts: Spread a thick layer of tomato jam on each slice of sourdough. Top with celery salad and transfer to serving plates. Ladle hollandaise on top and finish with cracked black pepper.