A model of a simple coaster, using the awesome infill patterns of Bambu Studio. The model is a simple cylinder with 90x90x5mm -- the trick is to set "Top shell layers" to 0, and then select the desired Sparse infill pattern and density. I also recommend 2 wall loops. You can change the model dimensions to fit your needs: increase the size in x or y to get an ellipse; increase both x and y for a larger diameter; increase z for a thicker coaster.

I included 7 profiles with different infill patterns. The ones that gave the best results are the grid, line, cubic, gyroid, honeycomb, hilbert curve and octagram spiral. Feel free to change the densities to get slightly different results.