- Place 12 2-ounce shot glasses in the freezer for at least 30 minutes.
- Place the tomato quarters into a food mill set over a clean bowl. Process until all liquid is extracted from tomatoes. Discard the solids. Strain tomato liquid through a fine-mesh sieve (should have about ¾ cup fresh tomato juice).
- Combine tomato juice with next 8 ingredients (horseradish through freshly ground black pepper). Chill mixture for at least 30 minutes before serving.
- Arrange 1 tablespoon of mixture in each prepared shot glass. Top each with one oyster and 1 tablespoon tequila. Repeat the layers one more time. Serve immediately.